Linux Blog

top 10 Ubuntu Games

noreply@blogger.com (Arun Tom) — Fri, 22 Jul 2011 02:45:00 +0000

Ubuntu 10.10/11.04 or any other Linux Based systems(such as – Open Suse, Linux Mint, Fedora etc.) has been lagging behind the windows when it comes to Games support. There are mainly two reasons that Linux based os isn’t the favorite platform of Gamers- First,Most of the commercial games are released just for Windows Platform; second the graphics card performance(probably due to the fact that Graphics Card Manufacturers do not release the appropriate drivers for Linux Platform,by the way if they releases proprietary(Closed Source) drivers then there is much possibility of compatibility issues with Linux based operating system).

The time has changed now,Linux based OS like Ubuntu is now becoming the favorite choice for gaming; mostly,due to availability of a large collection of open source and free games. Some commercial games developers has also concentrated on Ubuntu as their target platform. Nvidia Graphics card provides good performance on Ubuntu.

Top 10 Ubuntu Games – at a Glance

# 0 : Open Arena

Open Arena is an open source (and free) multiplayer FPS (First Person Shooter) game based on ioquake3 fork of the id tech 3 engine. it is the free version of quake III arena and it can stand alone so Quake III Arena is not required to play this game.

Download and installation instructions

If you are using Ubuntu 10.04/10.10 then download open arena deb and open with ‘Ubuntu Software Center’ (or open with ‘gdebi Package Manager’ in older versions of Ubuntu)to install. Visit the official wiki page of Open Arena- Installation Detailsfor other Linux Distributions.

# 1 : Torcs

Torcs is a 3D Racing Car Simulation Game based on OpenGL. it is available free for all platforms e.g Linux based OS(e.g Ubuntu 10.04/10.10/11.04),Windows,Mac OS X,BSD; available as an open source software.it has more than 50 cars,20 tracks and 50 opponents available for racing with lot of other features that brings reality during simulation.

Install Torcs on Ubuntu 10.04/10.10/11.04

>> Download the debian package – download torcs debian package

>> Open the *.deb with Ubuntu Software Center ; then click on install.

# 2 : Urban Terror

Urban Terror is a free multiplayer and multi-platform FPS(First Person Shooter) game similar to Quake I
II Arena.The motto of the game is ‘Fun Over Realism’ , so the game is very funky,enjoyable and unique.

Download Urban Terror

# 3 : Tux Racer

Tux Racer is fun and easy to learn - a 3D racing game(Licensed under GPL and available free to use) suitable for all ages.In this game you need to race through mountains; you will play the role of tux – Linux Mascot.it is available for all common platforms. The primary goal of the game is to slide-down a snow and ice-covered mountain as quickly as possible.

Download Tux Racer

On Ubuntu you can install Extreme Tux Racer(very similar to Tux Racer ) with one simple command(or from Synaptic Package Manager) – Open terminal and enter the command :

$ sudo apt-get install etuxracer

# 4 : Armagetron Advanced

Armagetron Advanced is a 3D game(open source,free and multi-platform), a clone of the movie Tron.This game is based on the light cycle racing which can take only 90 degrees turn(and leaves a solid wall behind the path) and the winner will be the one who will survive till last; without colliding with the walls.The other rule is that the it can’t stopped during the race.

Installing Armagetron on Ubuntu 10.04/10.10/11.04

Open Synaptic Package Manager and search for ‘armagetron advanced’ ; mark the boxes to select the package for installation; Finally click on Apply button to begin installation procedure.Wait for the installation to complete,then you are ready to play the game from Applications->Game menu.

# 5 : Vega Strike

Vega Strike is is a 3D space simulator game.it is free and open source; available for Linux/Mac/Windows.In vega strike,you can trade,fight and explore the vast universe with a lot of fun.it is developed on the top of OpenGL.

Download Vega Strike

# 6 : Battle of Wesnoth

it is a free turn based tactical strategy game with high fantasy theme.it is a multi platform game.

Download Battle of Wesnoth

# 7 : Nexuiz

Nexuiz is a 3D deathmatch game with very complex and high end graphics effects.it is open source and available free.You can play it using local network or Internet.

On Ubuntu you can install it in one click from the ‘Ubuntu Software Center’.

# 8 : Alien Arena

it is a 3D standalone online Deathmatch- FPS game based on Quake II/III Arena.it is open source and free.

it is also available in Ubuntu Software Center,so ubuntu users can install it from there.

# 9 : Vdrift

Vdrift is an open source and free game which simulates driving with vdrift features.The game is new and all the development goal haven’t been completed but it is still playable.

Ubuntu users can download the debian pckage of vdrift and install it by Right Click ->Open with Ubuntu Software Center and click on Install button.

That’s All..If you have any suggestion or opinion then let us know through comments.

Remote control your Linux with any mobile Phone

noreply@blogger.com (Arun Tom) — Tue, 19 Jul 2011 12:00:00 +0000

What is anyRemote?

The overall goal of this project is to provide remote control service on Linux through Bluetooth, InfraRed, Wi-Fi or just TCP/IP connection.

anyRemote supports wide range of modern cell phones like Nokia, SonyEricsson, Motorola and others.

It was developed as thin communication layer between Bluetooth (or IR, Wi-Fi) capabled phone and Linux, and in principle could be configured to manage almost any software.

anyRemote is console application, but in addition there are GUI front ends for Gnome and KDE.

Features

Plenty of connection variants

anyRemote can be used by:

bluetooth connection with java client if cell phone is JSR82 compatible

Wi-Fi connection with java client if phone supports Wi-Fi

IR connection with java client if java realization in phone supports access to IR port

ordinary TCP/IP connection with java client, if PC is connectable from internet
bluetooth, infrared or cable connection using AT "modem" commands
web interface

it supports some of IR remotes supplied with TV tuner cards (like LIRC)

it has limited support for Bemused clients

experimental support for iPhone/iPod Touch with Command Fusion's iViewer installed

Plenty of compatible phones

anyRemote should work with the following phones:

Nokia Series40 and Series60
Sony Ericsson
Motorola
BenqSiemens

You can find complete list of phones and other devices which were tested with anyRemote on the Devices List

Some phone-specific details described here.

Frontends

There are KDE and Gnome GUI frontends. In addition to this it is possible to control anyRemote with a web interface.

Free as in Freedom

anyRemote is Free Software and released under the GNU GPL license.

Linux Performance Monitoring and Tuning

noreply@blogger.com (Arun Tom) — Sat, 09 Jul 2011 17:48:00 +0000

Linux system administrators should be proficient in Linux performance monitoring and tuning. This article gives a high level overview on how we should approach performance monitoring and tuning in Linux, and the various subsystems (and performance metrics) that needs to be monitored.

To identify system bottlenecks and come up with solutions to fix it, you should understand how various components of Linux works. For example, how the kernel gives preference to one Linux process over others using nice values, how I/O interrupts are handled, how the memory management works, how the Linux file system works, how the network layer is implemented in Linux, etc.,

Please note that understanding how various components (or subsystems) works is not the same as knowing what command to execute to get certain output. For example, you might know that “uptime” or “top” command gives the “load average”. But, if you don’t know what it means, and how the CPU (or process) subsystem works, you might not be able to understand it properly. Understanding the subsystems is an on-going task, which you’ll be constantly learning all the time.

On a very high level, following are the four subsystems that needs to be monitored.

CPU
Memory
I/O
Network

1. CPU

You should understand the four critical performance metrics for CPU — context switch, run queue, cpu utilization, and load average.

Context Switch

When CPU switches from one process (or thread) to another, it is called as context switch.
When a process switch happens, kernel stores the current state of the CPU (of a process or thread) in the memory.
Kernel also retrieves the previously stored state (of a process or thread) from the memory and puts it in the CPU.
Context switching is very essential for multitasking of the CPU.
However, a higher level of context switching can cause performance issues.

Run Queue

Run queue indicates the total number of active processes in the current queue for CPU.
When CPU is ready to execute a process, it picks it up from the run queue based on the priority of the process.
Please note that processes that are in sleep state, or i/o wait state are not in the run queue.
So, a higher number of processes in the run queue can cause performance issues.

Cpu Utilization

This indicates how much of the CPU is currently getting used.
This is fairly straight forward, and you can view the CPU utilization from the top command.
100% CPU utilization means the system is fully loaded.
So, a higher %age of CPU utilization will cause performance issues.

Load Average

This indicates the average CPU load over a specific time period.
On Linux, load average is displayed for the last 1 minute, 5 minutes, and 15 minutes. This is helpful to see whether the overall load on the system is going up or down.
For example, a load average of “0.75 1.70 2.10″ indicates that the load on the system is coming down. 0.75 is the load average in the last 1 minute. 1.70 is the load average in the last 5 minutes. 2.10 is the load average in the last 15 minutes.
Please note that this load average is calculated by combining both the total number of process in the queue, and the total number of processes in the uninterruptable task status.

2. Network

A good understanding of TCP/IP concepts is helpful while analyzing any network issues. We’ll discuss more about this in future articles.
For network interfaces, you should monitor total number of packets (and bytes) received/sent through the interface, number of packets dropped, etc.,

3. I/O

I/O wait is the amount of time CPU is waiting for I/O. If you see consistent high i/o wait on you system, it indicates a problem in the disk subsystem.
You should also monitor reads/second, and writes/second. This is measured in blocks. i.e number of blocks read/write per second. These are also referred as bi and bo (block in and block out).
tps indicates total transactions per seconds, which is sum of rtps (read transactions per second) and wtps (write transactions per seconds).

4. Memory

As you know, RAM is your physical memory. If you have 4GB RAM installed on your system, you have 4GB of physical memory.
Virtual memory = Swap space available on the disk + Physical memory. The virtual memory contains both user space and kernel space.
Using either 32-bit or 64-bit system makes a big difference in determining how much memory a process can utilize.
On a 32-bit system a process can only access a maximum of 4GB virtual memory. On a 64-bit system there is no such limitation.
The unused RAM will be used as file system cache by the kernel.
The Linux system will swap when it needs more memory. i.e when it needs more memory than the physical memory. When it swaps, it writes the least used memory pages from the physical memory to the swap space on the disk.
Lot of swapping can cause performance issues, as the disk is much slower than the physical memory, and it takes time to swap the memory pages from RAM to disk.

All of the above 4 subsystems are interrelated. Just because you see a high reads/second, or writes/second, or I/O wait doesn’t mean the issue is there with the I/O sub-system. It also depends on what the application is doing. In most cases, the performance issue might be caused by the application that is running on the Linux system.

Remember the 80/20 rule — 80% of the performance improvement comes from tuning the application, and the rest 20% comes from tuning the infrastructure components.

There are various tools available to monitor Linux system performance. For example: top, free, ps, iostat, vmstat, mpstat, sar, tcpump, netstat, iozone, etc., We’ll be discussing more about these tools and how to use them in the upcoming articles in this series.

Following is the 4 step approach to identify and solve a performance issue.

Step 1 – Understand (and reproduce) the problem: Half of the problem is solved when you clearly understand what the problem is. Before trying to solve the performance issue, first work on clearly defining the problem. The more time you spend on understanding and defining the problem will give you enough details to look for the answers in the right place. If possible, try to reproduce the problem, or at least simulate a situation that you think closely resembles the problem. This will later help you to validate the solution you come up to fix the performance issue.
Step 2 – Monitor and collect data: After defining the problem clearly, monitor the system and try to collect as much data as possible on various subsystems. Based on this data, come up list of potential issues.
Step 3 – Eliminate and narrow down issues: After having a list of potential issues, dive into each one of them and eliminate any non issues. Narrow it down further to see whether it is an application issue, or an infrastructure issue. Drill down further and narrow it down to a specific component. For example, if it is an infrastructure issue, narrow it down and identify the subsystem that is causing the issue. If it is an I/O subsystem issue, narrow it down to a specific partition, or raid group, or LUN, or disk. Basically, keep drilling down until you put your finger on the root cause of the issue.
Step 4 – One change at a time: Once you’ve narrowed down to a small list of potential issues, don’t try to make multiple changes at one time. If you make multiple changes, you wouldn’t know which one fixed the original issue. Multiple changes at one time might also cause new issues, which you’ll be chasing after instead of fixing the original issue. So, make one change at a time, and see if it fixes the original problem.

In the upcoming articles of the performance series, we’ll discuss more about how to monitor and address performance issues on CPU, Memory, I/O and Network subsystem using various Linux performance monitoring tools.

20 Linux System Monitoring Tools

noreply@blogger.com (Arun Tom) — Sat, 09 Jul 2011 17:13:00 +0000

20 Linux System Monitoring Tools Every SysAdmin Should Know

Need to monitor Linux server performance? Try these built-in command and a few add-on tools. Most Linux distributions are equipped with tons of monitoring. These tools provide metrics which can be used to get information about system activities. You can use these tools to find the possible causes of a performance problem. The commands discussed below are some of the most basic commands when it comes to system analysis and debugging server issues such as:

Finding out bottlenecks.
Disk (storage) bottlenecks.
CPU and memory bottlenecks.
Network bottlenecks.

#1: top - Process Activity Command

The top program provides a dynamic real-time view of a running system i.e. actual process activity. By default, it displays the most CPU-intensive tasks running on the server and updates the list every five seconds.

Commonly Used Hot Keys

The top command provides several useful hot keys:

Hot Key	Usage
t	Displays summary information off and on.
m	Displays memory information off and on.
A	Sorts the display by top consumers of various system resources. Useful for quick identification of performance-hungry tasks on a system.
f	Enters an interactive configuration screen for top. Helpful for setting up top for a specific task.
o	Enables you to interactively select the ordering within top.
r	Issues renice command.
k	Issues kill command.
z	Turn on or off color/mono

#2: vmstat - System Activity, Hardware and System Information

The command vmstat reports information about processes, memory, paging, block IO, traps, and cpu activity.

# vmstat 3
Sample Outputs:

procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
 0  0      0 2540988 522188 5130400    0    0     2    32    4    2  4  1 96  0  0
 1  0      0 2540988 522188 5130400    0    0     0   720 1199  665  1  0 99  0  0
 0  0      0 2540956 522188 5130400    0    0     0     0 1151 1569  4  1 95  0  0
 0  0      0 2540956 522188 5130500    0    0     0     6 1117  439  1  0 99  0  0
 0  0      0 2540940 522188 5130512    0    0     0   536 1189  932  1  0 98  0  0
 0  0      0 2538444 522188 5130588    0    0     0     0 1187 1417  4  1 96  0  0
 0  0      0 2490060 522188 5130640    0    0     0    18 1253 1123  5  1 94  0  0

Display Memory Utilization Slabinfo

# vmstat -m

Get Information About Active / Inactive Memory Pages

# vmstat -a

#3: w - Find Out Who Is Logged on And What They Are Doing

w command displays information about the users currently on the machine, and their processes.

# w username
# w arun

Sample Outputs:

17:58:47 up 5 days, 20:28,  2 users,  load average: 0.36, 0.26, 0.24
USER     TTY      FROM              LOGIN@   IDLE   JCPU   PCPU WHAT
root     pts/0    10.1.3.145       14:55    5.00s  0.04s  0.02s vim /etc/resolv.conf
root     pts/1    10.1.3.145       17:43    0.00s  0.03s  0.00s w

#4: uptime - Tell How Long The System Has Been Running

The uptime command can be used to see how long the server has been running. The current time, how long the system has been running, how many users are currently logged on, and the system load averages for the past 1, 5, and 15 minutes.
# uptime
Output:

18:02:41 up 41 days, 23:42,  1 user,  load average: 0.00, 0.00, 0.00

1 can be considered as optimal load value. The load can change from system to system. For a single CPU system 1 - 3 and SMP systems 6-10 load value might be acceptable.

#5: ps - Displays The Processes

ps command will report a snapshot of the current processes. To select all processes use the -A or -e option:
# ps -A
Sample Outputs:

PID TTY          TIME CMD
    1 ?        00:00:02 init
    2 ?        00:00:02 migration/0
    3 ?        00:00:01 ksoftirqd/0
    4 ?        00:00:00 watchdog/0
    5 ?        00:00:00 migration/1
    6 ?        00:00:15 ksoftirqd/1
....
.....
 4881 ?        00:53:28 java
 4885 tty1     00:00:00 mingetty
 4886 tty2     00:00:00 mingetty
 4887 tty3     00:00:00 mingetty
 4888 tty4     00:00:00 mingetty
 4891 tty5     00:00:00 mingetty
 4892 tty6     00:00:00 mingetty
 4893 ttyS1    00:00:00 agetty
12853 ?        00:00:00 cifsoplockd
12854 ?        00:00:00 cifsdnotifyd
14231 ?        00:10:34 lighttpd
14232 ?        00:00:00 php-cgi
54981 pts/0    00:00:00 vim
55465 ?        00:00:00 php-cgi
55546 ?        00:00:00 bind9-snmp-stat
55704 pts/1    00:00:00 ps

ps is just like top but provides more information.

Show Long Format Output

# ps -Al
To turn on extra full mode (it will show command line arguments passed to process):
# ps -AlF

To See Threads ( LWP and NLWP)

# ps -AlFH

To See Threads After Processes

# ps -AlLm

Print All Process On The Server

# ps ax
# ps axu

Print A Process Tree

# ps -ejH
# ps axjf
# pstree

Print Security Information

# ps -eo euser,ruser,suser,fuser,f,comm,label
# ps axZ
# ps -eM

See Every Process Running As User Arun

# ps -U vivek -u arun u

Set Output In a User-Defined Format

# ps -eo pid,tid,class,rtprio,ni,pri,psr,pcpu,stat,wchan:14,comm
# ps axo stat,euid,ruid,tty,tpgid,sess,pgrp,ppid,pid,pcpu,comm
# ps -eopid,tt,user,fname,tmout,f,wchan

Display Only The Process IDs of Lighttpd

# ps -C lighttpd -o pid=
OR
# pgrep lighttpd
OR
# pgrep -u arun php-cgi

Display The Name of PID 55977

# ps -p 55977 -o comm=

Find Out The Top 10 Memory Consuming Process

# ps -auxf | sort -nr -k 4 | head -10

Find Out top 10 CPU Consuming Process

# ps -auxf | sort -nr -k 3 | head -10

#6: free - Memory Usage

The command free displays the total amount of free and used physical and swap memory in the system, as well as the buffers used by the kernel.
# free
Sample Output:

total       used       free     shared    buffers     cached
Mem:      12302896    9739664    2563232          0     523124    5154740
-/+ buffers/cache:    4061800    8241096
Swap:      1052248          0    1052248

#7: iostat - Average CPU Load, Disk Activity

The command iostat report Central Processing Unit (CPU) statistics and input/output statistics for devices, partitions and network filesystems (NFS).
# iostat
Sample Outputs:

Linux 2.6.18-128.1.14.el5 (www03.nixcraft.in)  06/26/2009

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           3.50    0.09    0.51    0.03    0.00   95.86

Device:            tps   Blk_read/s   Blk_wrtn/s   Blk_read   Blk_wrtn
sda              22.04        31.88       512.03   16193351  260102868
sda1              0.00         0.00         0.00       2166        180
sda2             22.04        31.87       512.03   16189010  260102688
sda3              0.00         0.00         0.00       1615          0

#8: sar - Collect and Report System Activity

The sar command is used to collect, report, and save system activity information. To see network counter, enter:
# sar -n DEV | more
To display the network counters from the 24th:
# sar -n DEV -f /var/log/sa/sa24 | more
You can also display real time usage using sar:
# sar 4 5
Sample Outputs:

Linux 2.6.18-128.1.14.el5 (www03.nixcraft.in)   06/26/2009

06:45:12 PM       CPU     %user     %nice   %system   %iowait    %steal     %idle
06:45:16 PM       all      2.00      0.00      0.22      0.00      0.00     97.78
06:45:20 PM       all      2.07      0.00      0.38      0.03      0.00     97.52
06:45:24 PM       all      0.94      0.00      0.28      0.00      0.00     98.78
06:45:28 PM       all      1.56      0.00      0.22      0.00      0.00     98.22
06:45:32 PM       all      3.53      0.00      0.25      0.03      0.00     96.19
Average:          all      2.02      0.00      0.27      0.01      0.00     97.70

#9: mpstat - Multiprocessor Usage

The mpstat command displays activities for each available processor, processor 0 being the first one. mpstat -P ALL to display average CPU utilization per processor:
# mpstat -P ALL
Sample Output:

Linux 2.6.18-128.1.14.el5 (www03.nixcraft.in)   06/26/2009

06:48:11 PM  CPU   %user   %nice    %sys %iowait    %irq   %soft  %steal   %idle    intr/s
06:48:11 PM  all    3.50    0.09    0.34    0.03    0.01    0.17    0.00   95.86   1218.04
06:48:11 PM    0    3.44    0.08    0.31    0.02    0.00    0.12    0.00   96.04   1000.31
06:48:11 PM    1    3.10    0.08    0.32    0.09    0.02    0.11    0.00   96.28     34.93
06:48:11 PM    2    4.16    0.11    0.36    0.02    0.00    0.11    0.00   95.25      0.00
06:48:11 PM    3    3.77    0.11    0.38    0.03    0.01    0.24    0.00   95.46     44.80
06:48:11 PM    4    2.96    0.07    0.29    0.04    0.02    0.10    0.00   96.52     25.91
06:48:11 PM    5    3.26    0.08    0.28    0.03    0.01    0.10    0.00   96.23     14.98
06:48:11 PM    6    4.00    0.10    0.34    0.01    0.00    0.13    0.00   95.42      3.75
06:48:11 PM    7    3.30    0.11    0.39    0.03    0.01    0.46    0.00   95.69     76.89

#10: pmap - Process Memory Usage

The command pmap report memory map of a process. Use this command to find out causes of memory bottlenecks.
# pmap -d PID
To display process memory information for pid # 47394, enter:
# pmap -d 47394
Sample Outputs:

47394:   /usr/bin/php-cgi
Address           Kbytes Mode  Offset           Device    Mapping
0000000000400000    2584 r-x-- 0000000000000000 008:00002 php-cgi
0000000000886000     140 rw--- 0000000000286000 008:00002 php-cgi
00000000008a9000      52 rw--- 00000000008a9000 000:00000   [ anon ]
0000000000aa8000      76 rw--- 00000000002a8000 008:00002 php-cgi
000000000f678000    1980 rw--- 000000000f678000 000:00000   [ anon ]
000000314a600000     112 r-x-- 0000000000000000 008:00002 ld-2.5.so
000000314a81b000       4 r---- 000000000001b000 008:00002 ld-2.5.so
000000314a81c000       4 rw--- 000000000001c000 008:00002 ld-2.5.so
000000314aa00000    1328 r-x-- 0000000000000000 008:00002 libc-2.5.so
000000314ab4c000    2048 ----- 000000000014c000 008:00002 libc-2.5.so
.....
......
..
00002af8d48fd000       4 rw--- 0000000000006000 008:00002 xsl.so
00002af8d490c000      40 r-x-- 0000000000000000 008:00002 libnss_files-2.5.so
00002af8d4916000    2044 ----- 000000000000a000 008:00002 libnss_files-2.5.so
00002af8d4b15000       4 r---- 0000000000009000 008:00002 libnss_files-2.5.so
00002af8d4b16000       4 rw--- 000000000000a000 008:00002 libnss_files-2.5.so
00002af8d4b17000  768000 rw-s- 0000000000000000 000:00009 zero (deleted)
00007fffc95fe000      84 rw--- 00007ffffffea000 000:00000   [ stack ]
ffffffffff600000    8192 ----- 0000000000000000 000:00000   [ anon ]
mapped: 933712K    writeable/private: 4304K    shared: 768000K

The last line is very important:

mapped: 933712K total amount of memory mapped to files
writeable/private: 4304K the amount of private address space
shared: 768000K the amount of address space this process is sharing with others

#11 and #12: netstat and ss - Network Statistics

The command netstat displays network connections, routing tables, interface statistics, masquerade connections, and multicast memberships. ss command is used to dump socket statistics. It allows showing information similar to netstat. See the following resources about ss and netstat commands:

ss: Display Linux TCP / UDP Network and Socket Information
Get Detailed Information About Particular IP address Connections Using netstat Command

#13: iptraf - Real-time Network Statistics

The iptraf command is interactive colorful IP LAN monitor. It is an ncurses-based IP LAN monitor that generates various network statistics including TCP info, UDP counts, ICMP and OSPF information, Ethernet load info, node stats, IP checksum errors, and others. It can provide the following info in easy to read format:

Network traffic statistics by TCP connection
IP traffic statistics by network interface
Network traffic statistics by protocol
Network traffic statistics by TCP/UDP port and by packet size
Network traffic statistics by Layer2 address

Fig.02: General interface statistics: IP traffic statistics by network interface

Fig.03 Network traffic statistics by TCP connection

#14: tcpdump - Detailed Network Traffic Analysis

The tcpdump is simple command that dump traffic on a network. However, you need good understanding of TCP/IP protocol to utilize this tool. For.e.g to display traffic info about DNS, enter:
# tcpdump -i eth1 'udp port 53'
To display all IPv4 HTTP packets to and from port 80, i.e. print only packets that contain data, not, for example, SYN and FIN packets and ACK-only packets, enter:
# tcpdump 'tcp port 80 and (((ip[2:2] - ((ip[0]&0xf)<<2)) - ((tcp[12]&0xf0)>>2)) != 0)'
To display all FTP session to 202.54.1.5, enter:
# tcpdump -i eth1 'dst 202.54.1.5 and (port 21 or 20'
To display all HTTP session to 192.168.1.5:
# tcpdump -ni eth0 'dst 192.168.1.5 and tcp and port http'
Use wireshark to view detailed information about files, enter:
# tcpdump -n -i eth1 -s 0 -w output.txt src or dst port 80

#15: strace - System Calls

Trace system calls and signals. This is useful for debugging webserver and other server problems. See how to use to trace the process and see What it is doing.

#16: /Proc file system - Various Kernel Statistics

/proc file system provides detailed information about various hardware devices and other Linux kernel information. See Linux kernel /proc documentations for further details. Common /proc examples:

# cat /proc/cpuinfo
# cat /proc/meminfo
# cat /proc/zoneinfo
# cat /proc/mounts

17#: Nagios - Server And Network Monitoring

Nagios is a popular open source computer system and network monitoring application software. You can easily monitor all your hosts, network equipment and services. It can send alert when things go wrong and again when they get better. FAN is "Fully Automated Nagios". FAN goals are to provide a Nagios installation including most tools provided by the Nagios Community. FAN provides a CDRom image in the standard ISO format, making it easy to easilly install a Nagios server. Added to this, a wide bunch of tools are including to the distribution, in order to improve the user experience around Nagios.

18#: Cacti - Web-based Monitoring Tool

Cacti is a complete network graphing solution designed to harness the power of RRDTool's data storage and graphing functionality. Cacti provides a fast poller, advanced graph templating, multiple data acquisition methods, and user management features out of the box. All of this is wrapped in an intuitive, easy to use interface that makes sense for LAN-sized installations up to complex networks with hundreds of devices. It can provide data about network, CPU, memory, logged in users, Apache, DNS servers and much more. See how to install and configure Cacti network graphing tool under CentOS / RHEL.

#19: KDE System Guard - Real-time Systems Reporting and Graphing

KSysguard is a network enabled task and system monitor application for KDE desktop. This tool can be run over ssh session. It provides lots of features such as a client/server architecture that enables monitoring of local and remote hosts. The graphical front end uses so-called sensors to retrieve the information it displays. A sensor can return simple values or more complex information like tables. For each type of information, one or more displays are provided. Displays are organized in worksheets that can be saved and loaded independently from each other. So, KSysguard is not only a simple task manager but also a very powerful tool to control large server farms.

Fig.05 KDE System Guard {Image credit: Wikipedia}

See the KSysguard handbook for detailed usage.

#20: Gnome System Monitor - Real-time Systems Reporting and Graphing

The System Monitor application enables you to display basic system information and monitor system processes, usage of system resources, and file systems. You can also use System Monitor to modify the behavior of your system. Although not as powerful as the KDE System Guard, it provides the basic information which may be useful for new users:

Displays various basic information about the computer's hardware and software.
Linux Kernel version
GNOME version
Hardware
Installed memory
Processors and speeds
System Status
Currently available disk space
Processes
Memory and swap space
Network usage
File Systems
Lists all mounted filesystems along with basic information about each.

Fig.06 The Gnome System Monitor application

Bonus: Additional Tools

A few more tools:

nmap - scan your server for open ports.
lsof - list open files, network connections and much more.
ntop web based tool - ntop is the best tool to see network usage in a way similar to what top command does for processes i.e. it is network traffic monitoring software. You can see network status, protocol wise distribution of traffic for UDP, TCP, DNS, HTTP and other protocols.
Conky - Another good monitoring tool for the X Window System. It is highly configurable and is able to monitor many system variables including the status of the CPU, memory, swap space, disk storage, temperatures, processes, network interfaces, battery power, system messages, e-mail inboxes etc.
GKrellM - It can be used to monitor the status of CPUs, main memory, hard disks, network interfaces, local and remote mailboxes, and many other things.
vnstat - vnStat is a console-based network traffic monitor. It keeps a log of hourly, daily and monthly network traffic for the selected interface(s).
htop - htop is an enhanced version of top, the interactive process viewer, which can display the list of processes in a tree form.
mtr - mtr combines the functionality of the traceroute and ping programs in a single network diagnostic tool.

Did I miss something? Please add your favorite system motoring tool in the comments.

Hack DNS for Faster Web Browsing (increase internet speed)

noreply@blogger.com (Arun Tom) — Fri, 08 Jul 2011 16:40:00 +0000

What is DNS? Domain Name System (DNS) is like a phone book, but for Internet. DNS translates human-readable computer hostnames, e.g. www.linuxblog.co.cc , into an IP address needed by the networking equipment to deliver information. In other words, when you open your browser and type an URL in the address bar , e.g. www.linuxblog.co.cc , the DNS server translates that URL into a numeric IP address, from www.linuxblog.co.cc to xxx.xxx.x.x.
Now, if you have a DSL, ADSL, Dial-up or FIOS (fiber-optic service) Internet connection, you must understand that your computer uses the default DNS server(s) from your Internet Service Provider (ISP) and if this DNS server is slow in resolving URLs, you (the victim) will see that almost all the web pages that you try to access, are loading slow. So, practically it doesn't matter how fast your Internet pipe is. For example, you can be the proud owner of a 1 Gbps bandwith,but if the DNS servers from your ISP are slow, your web surfing will be slow too.

What can you do to fix this? You can call or go to your ISP and complain about this problem, until you get tired probably, or you can continue reading this guide in order to improve your web surfing sessions.

Use OpenDNS - Make your Internet better

Probably you have figured it out already that you must change your DNS servers, in order to speed up your web surfing. And to achieve this, you will have to use the OpenDNS service, which is the #1 DNS service provider around the world.
OpenDNS is FREE and requires nothing to download. Moreover, it will not replace your existing Internet connection, it will just make it better. Also, OpenDNS offers some other free services, like the possibility to have your personal web shortcuts. For more information about OpenDNS please visit the official home page.

Here is what you must do. Please back up your DNS addresses before replacing them with the ones from OpenDNS, in case you want to return to them later for any reason. The DNS server addresses for OpenDNS are:208.67.222.222
208.67.220.220

For Static IP address

If you have a static IP address that you must manually configure in order to have Internet access, please use the following method.

Open a console and type:

CODE

sudo gedit /etc/resolv.conf

and add the following lines, above the existing lines in that file:nameserver 208.67.222.222
nameserver 208.67.220.220

For Dynamic IP address (DHCP)

If you use a dynamic IP address (DHCP), that means you get your Internet IP address, subnet mask, DNS and gateway automatically from your ISP's DHCP server, please follow the instructions below:

CODE

sudo gedit /etc/dhcp3/dhclient.conf

Replace the line that says:

#prepend domain-name-servers 127.0.0.1;

with this one:

prepend domain-name-servers 208.67.222.222, 208.67.220.220;

Restart your network for the changes to take effect:

CODE

sudo /etc/init.d/networking restart

For Ubuntu users

If you use Ubuntu, please go to System -> Administration -> Networking, click on the third tab (DNS) and add, one by one, the OpenDNS addresses on top of the first field (DNS Servers). Close the window and restart your computer.

What now? Visit http://welcome.opendns.com/ to test your new settings. If you see a web page that says: Welcome to OpenDNS! Your Internet is safer, faster, and smarter because you're using OpenDNS. Thank you!, then you're back in business! Enjoy your lightning-fast Internet connection!

Broadband ONLY Hacks

For broadband user ONLY, please add the following lines (copy/paste) in your /etc/sysctl.conffile. Open a console and type:

CODE

sudo gedit /etc/sysctl.conf

and paste this:

# Tweaks for faster broadband...
net.core.rmem_default = 524288
net.core.rmem_max = 524288
net.core.wmem_default = 524288
net.core.wmem_max = 524288
net.ipv4.tcp_wmem = 4096 87380 524288
net.ipv4.tcp_rmem = 4096 87380 524288
net.ipv4.tcp_mem = 524288 524288 524288
net.ipv4.tcp_rfc1337 = 1
net.ipv4.ip_no_pmtu_disc = 0
net.ipv4.tcp_sack = 1
net.ipv4.tcp_fack = 1
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_timestamps = 1
net.ipv4.tcp_ecn = 0
net.ipv4.route.flush = 1

Then type the following code in the console, in order to activate the settings immediately:

CODE

sysctl -p

This guide was successfully tested on an Ubuntu 7.04 machine.

Open a console and type:

Installation Guide : Fedora 15

noreply@blogger.com (Arun Tom) — Fri, 08 Jul 2011 15:39:00 +0000

Things you need to get started?

· You will need one of the Fedora 15 Live CD ISO images that corresponds to your hardware architecture (i386 or amd64), and which can be downloaded from fedora home page.
· You will need a 700 MB CD, because when the download will finish, you need to burn the ISO image with your favorite CD/DVD burning application (Brasero on Linux, or Nero, CDBurnerXP, Roxio on Windows).
· You must have a minimum of 10 GB free space on your hard drive, for the Fedora 15 installation.

Great, now let's begin. Insert or leave the CD in your CD/DVD-ROM device, and reboot the computer in order to boot from it. Hit the F8 or F12 key (depending on your BIOS) to select the CD/DVD-ROM as the boot device. Boot from the CD.

Fedora 15 will automatically boot in 10 seconds.

Wait for the system to load.......

In a couple of minutes you will be greeted by the new GNOME 3 environment...

Go to the Activities button on the left side of the panel and click on the "Install to Hard Drive" icon, or in case you don't have 3D support go to Applications -> System Tools -> Install to Hard Drive. The installation wizard will appear.

Choose your language...

When you will be asked what type of devices will your installation involve, choose the "Basic Storage Devices" if you are a regular user and you just want to install Fedora on your regular hard drive. Click the Next button...

Choose a name for your computer and click on the Next button...

Select the nearest city in your time zone and click the Next button...

Type in a password (twice) for the root account (system administrator) and click the Next button...

When you will be asked which type of installation would you like, you have several options to choose from. For example, you can install Fedora 15 alongside another operating system, such as Ubuntu 11.04 or Windows 7, if you choose the "Use Free Space" option. But if you want to install Fedora 15 and erase all the data on your hard drive, you must choose the first option - "Use All Space".

At this step you can also choose to encrypt your entire hard drive, by checking the "Encrypt system" option.

Whichever you choose, click the Next button to continue...

You will be warned that all your data on the existing hard drive will be deleted. Click the "Write changes to disk" button when asked...

The hard drive will be formatted and the partitions will be created...

Everything will be done automatically from now on, just sit back and watch how the Live CD packages are copied to your hard drive. The installation process will take about 8-10 minutes (depending on your computer specs and the selected packages).

When the installation is over, you will get a "Congratulations, the installation is complete" screen. Click the "Reboot" button and your computer will automatically restart...

Remove the Live CD from your optical drive. Your brand new Fedora 15 operating system will boot for the first time...

If you've chosen to encrypt your partition, then you'll be prompted for the passphrase...

The system will continue to boot and in a few seconds you will see the First Boot Configuration Wizard. Click "Forward" on the Welcome screen...

Click "Forward" on the License screen...

Create a regular user for the system...

Set the date and time...

Send your hardware profile to the Fedora Project (optional)...

Click "Finish" and you will see the login screen. Enter the password for the regular user you've just created...

That's it! Enjoy the ultimate and breathtaking Fedora 15 Linux distribution!

Play Windows games on Linux with Crossover

noreply@blogger.com (Arun Tom) — Fri, 08 Jul 2011 12:57:00 +0000

CrossOver Games is an addition to the popular CrossOver series. Unlike other CrossOver products, which are aimed primarily at office productivity applications, CrossOver Games focuses on the stability of installing Windows games on Linux (and Mac OSX). As the same as PlayOnLinux, CrossOver Games provides a click and install method that makes it simple for anyone to use. The latest version of CrossOver Games has already tested to work with more than a hundred Windows games, including the popular World of Warcraft, Half-Life2 and Counterstrike.

Crossing over

When it comes to playing the games, Crossover Games is relatively straightforward to use. And in comparison to getting certain SecuROM titles to work on Windows, it can be considerably easier. But your first step has to be a check for compatibility.

Crossover hosts an online database that lists around 200 games titles that are known to work, and a few that don't. Compatibility is graded by gold, silver and bronze awards, and if your game wins any of these, you should be able to play it through without too much difficulty. Crossover judges compatibility against its own very high standards, and tries to be completely truthful about the faithfulness of a working game.

It's for this reason that there isn't a single game that has been awarded a gold medal, but there are over 20 with the silver title. According to Crossover's standards, this means the silver games 'install and run well enough to be useable', and titles include many Valve titles such as the Half Life 2 Episodes 1&2,Portal and Team Fortress 2. World of Warcraft, EVE Online and Guild Wars are reported to run well, and the latest 7.2 release of Crossover adds better support for Spore and City of Heroes.

UPDATES: The latest release of Crossover adds better support for games like Spore

In our experience, performance is usually a little below the equivalent XP speed. Using the Half Life: Lost Coast benchmark as an example, the Linux version (with the same settings) ran around 20 per cent slower, which doesn't make any difference considering the age of the game and that most modern hardware should be able to run it without difficulty.

Even if a title isn't in the database, it doesn't mean you definitely won't be able to run it. WINE, and henceCrossover Games, attempts to run any Windows executable you throw at it. If you like games from earlier on in the decade, for instance, there's a good chance that these games will run without any mention of their compatibility in the database. But you might also have some luck with newer games.

We were able to get Oblivion and S.T.A.L.K.E.R. to run by clicking on the executable from our shared Windows partition, although we couldn't perform the same trick with Bioshock, presumably because of the copy protection. We were also able to successfully run the Steam.EXE in the same way, running it from a mounted Windows partition. Steam even found the installed games list from our Windows installation, which saved both the space and effort from downloading them twice.

Steam is one of the best reasons for using Crossover. Thanks to its civilised anti-piracy mechanism and the download model, plenty of games and demos in its roster will run. From the Crossover application window, you can download and install and run the latest Steam client, which will in turn download your games to the Linux desktop. And if they don't work, you can always revert to Windows and use the same Steam account and play the game that way.

STEAMING: Counter Strike Source is one of the games you should be able to play with Crossover Games

Our biggest problem came from using a dual monitor configuration in Linux, as most games could only detect this as a single massive resolution through Crossover. Fortunately, there are two solutions. Either use the game's properties field to set a screen resolution or windowed mode, or force a virtual resolution in the Crossover Games configuration panel.

In our experience, Linux is much better at running a game within a window alongside your normal desktop applications, which can be a real boon if you like to run more than one EVE account at the same time.

The competition

If you want to delve into the details, there's plenty of room to change things in Crossover. Games are installed into something called a 'bottle', which is a term for a separate virtual Windows installation. This means you can keep bottles completely isolated from one another so that there's no conflict with shared libraries or other files. It also means one bottle can emulate Windows XP, while another could attempt Windows 2000 or Vista.

These options are dynamic, and you can change almost anything about each bottle through a properties manager that looks and feels much like the real thing on Windows. If you're looking to run Bioshock andOblivion then there's a competitor to Crossover that will run both without problems.

Transgaming's Cedega is a private and purely commercial fork of the WINE project. It doesn't release its modifications back to the WINE project, and it uses a subscription model to keep its customers up-to- date. If your subscription ends, you'll still be able to use the software, you just won't benefit from any updates.

While this closed model goes against the philosophy of using Linux it does offer the Transgaming developers certain advantages. The biggest of which is their ability to licence the official anti-piracy code so that games can be installed and run from the original optical media. The result is that games likeBioshock run well on Cedega, along with over 40 other games that have been certified.

For several years, Cedega was the chosen platform for the semi-official EVE Online client on Linux. Using a slightly modified Windows executable tested for compatibility with WINE, it enabled Linux users to play EVE Online on their desktops. But in February this year, EVE support came to an end. The producer in charge of both the Linux and Mac clients cited lack of growth in the Linux market for the decision, and it seemed clear from the tone of his message that Linux uptake had been disappointing.

Fortunately, the game isn't over for EVE heads. Cedega still certifies the game as compatible, and the standalone premium Windows client seems to work well on Crossover Games. Many EVE users have even reported success using an ordinary WINE installation.

Supporting DX 10

In March, the CEO of the company behind Crossover – Jeremy White – laid out a roadmap for future development. He mentioned that his developers had spent the last year working hard on under-the-hood improvement such as .NET support, Gdiplus and DirectX.

As a result of this hard work, DirectX 9 compatibility is looking good in both Crossover Games and WINE. But his plans for the next release include the far more ambitious DirectX 10, and if development goes well, there may be a compatible version of Crossover Games released by the end of the year.

If Codeweavers can achieve this magic trick, there's a good chance that WINE could even be ported back to Windows, bringing DirectX 10 compatibility to older versions of Windows, such as XP and 2000, an irony that won't be lost on Linux users. While it's obvious that Linux is never going to be a hard-core gaming platform, Linux is also far from being a barren wasteland.

Technology like WINE and Crossover present enough potential to satisfy most persistent gaming urges, and over the course of the next 12 months, the situation is only likely to improve for Linux games. There's also a world of independent, free and open source gaming to delve into as well, and commercial small scale games like World of Goo have been very successful on the Linux desktop.

Windows is not so secure ?

noreply@blogger.com (Arun Tom) — Thu, 07 Jul 2011 18:52:00 +0000

1.user can take ownership of any system files

open notepad.exe and type

Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT\*\shell\runas]
@="Take Ownership"
"NoWorkingDirectory"=""
[HKEY_CLASSES_ROOT\*\shell\runas\command]
@="cmd.exe /c takeown /f \"%1\" && icacls \"%1\" /grant administrators:F"
"IsolatedCommand"="cmd.exe /c takeown /f \"%1\" && icacls \"%1\" /grant administrators:F"
[HKEY_CLASSES_ROOT\Directory\shell\runas]
@="Take Ownership"
"NoWorkingDirectory"=""
[HKEY_CLASSES_ROOT\Directory\shell\runas\command]
@="cmd.exe /c takeown /f \"%1\" /r /d y && icacls \"%1\" /grant administrators:F /t"
"IsolatedCommand"="cmd.exe /c takeown /f \"%1\" /r /d y && icacls \"%1\" /grant administrators:F /t"

save as *(any name).reg

invoke the file , this will patch windows registry . so their will be "take ownership" option in the context menu (appear on right click).

2. windows 7 system files can be easily modified .

So here is a list of various system files in Windows 7 which can be easily hacked using Resource Hacker:

Approx. all Windows 7 system icons

Login Screen Background -> %windir%\System32\imageres.dll

Login Screen image resources -> %windir%\System32\authui.dll

Startup Sound -> %windir%\System32\imageres.dll

Start ORB images -> %windir%\Explorer.exe -> Bitmap -> 6801 - 681
2 -> %windir%\System32\imageres.dll

Windows Version Image in "About Windows" dialog box -> %windir%\Branding\Basebrd\basebrd.dll

Windows Version Image in bottom of Login Screen -> %windir%\Branding\Basebrd\basebrd.dll

Control Panel Left Sidebar Image -> %windir%\System32\Shell32.dll -> Bitmap -> 632 & 633

Getting Started (aka Welcome Center) Images -> %windir%\System32\oobefldr.dll

Laptop Battery Meter image resources -> %windir%\System32\batmeter.dll

Internet Explorer 8 (IE8) Resources -> %windir%\System32\ieframe.dll

Windows Media Player 12 (WMP12) Resources -> %windir%\System32\wmploc.dll

Above mentioned system files/locations are new to Windows 7 and were not present in earlier Windows versions, like XP. If you want to change look of other menus, dialog boxes like RUN, Progress, System Properties, Start menu, Taskbar Properties, etc, you'll have to edit some other system files which you needed to edit in Windows XP But there is a little difference, now those files don't contain the resources but their .MUI files do.

For example in Windows XP, RUN dialog box resources were present in "%windir%\System32\Shell32.dll" file but in Windows 7, the resources are present in "%windir%\System32\en-US\Shell32.dll.mui" file.

All these .MUI files are present in any of following 2 locations:
%windir%\en-US\
%windir%\System32\en-US\

3. windows 7 administrator passwords can be easily hacked
a. by utilities like KONBOOT

Rather than cracking a Windows password, KON-BOOT bypasses it and lets you into the computer without typing one in. Then, when you restart, everything is back to normal.

b. by deleting system files

boot your system with any live CD
Go to location windows->system32->config
. And delete SAM.exe and SAM.log
done.

c. by the command prompt method

be a Linux user , enjoy the security

n the Command Prompt you can monitor all the user of the computer by typing some commands.

1: Press Win Key+R and type cmd in the Run command box and hit enter to open command prompt. And then type net user in the command prompt and hit Enter. The Command Prompt will show you all accounts on the Windows 7 PC.

2: Type net user xyz (xyz is the locked admin account's name and 123 is the new password) and press Enter. Now you have successfully created a new password on the locked admin account.

3: Type shutdown -r -t 00 and press Enter.

Your Windows 7 PC should be rebooted automatically and then you can log in Windows 7 with the new password. It is a simple and easy way to change the password of any users from the Command Prompt.

But the drawback of this technique is that you can’t solve Windows 7 password recovery issues if you do not have the Administrator Privilege. So it is quite hard to change the Windows password of the users without logging in as the administrator.

there are a lot more ways to loot your data in windows. windows is not secure for multiple users , they are only for home computing or personal use.

so BE A LINUX USER and ENJOY THE SECURITY,ENJOY THE FREEDOM

LILO and boot problems

noreply@blogger.com (Arun Tom) — Wed, 06 Jul 2011 18:16:00 +0000

When a computer starts, the number of beeps the BIOS outputs tells you the state of the computer. On some
computers, one beep means all is ok, but 2 beeps mean there is an error. LILO uses the same kind of codes.
The number of letters you see from the word LILO on the screen says what is wrong. The whole word means
everything is fine, only LI means only the first part of LILO could be loaded. A full description of this is
available from the Bootdisk HOWTO.
When LILO can't load, it's a major problem. This often means that the boot code was corrupted. The only
way to boot is from a floppy disk. In RedHat, you can use the rescue disk, in Slackware, you can use the boot
disk with the "mount" image.
When LILO is fine, it's often easier to figure a boot problem. If the kernel panics when it tries to boot, it is
usualy due to a configuration error. You can tell LILO to mount another kernel you may have, like a "safe" or
"old" image you kept for these cases. If the problem is in initialization scripts, you can tell LILO to boot
directly into a shell with the following boot command line:
LILO boot: linux init=/bin/sh
Where "linux" would be your kernel image

Repair A Corrupt MBR And Boot Into Linux with Fedora CD

noreply@blogger.com (Arun Tom) — Wed, 06 Jul 2011 18:13:00 +0000

There are times when you inadvertently overwrite your Master Boot Record. The end result being that you are unable to boot into Linux. This is especially true when you are dual booting between windows and Linux OSes. Once when I was working in Windows XP, I accidentally clicked the hibernate button instead of shutdown. And windows somehow overwrote my MBR which housed the GRUB boot loader. At such times, it pays to have this cool tip at hand.

This is what you do to restore the GRUB boot loader when faced with the above problem. First you need a Linux distribution CD. If you are using Fedora (RedHat) then the first CD is sufficient. But you may also use any of the live CDs like Knoppix, Ubuntu Live CD and so on.

With Fedora CD :

Boot your computer with the first CD of Fedora in your CD drive (You have to enable your PC to boot from the cdrom, which you can set in the BIOS settings). At the installation boot prompt that you get, enter the following command:

boot: linux rescue

... and press Enter. The installer will ask you a few questions like the language you would like to use, the type of keyboard etc. Then, if you have linux previously installed on your machine, the Fedora installer will automatically detect it and mount it in the /mnt/sysimage directory. Once the linux partition is mounted, you are dropped into the command shell prompt. The next step is to make your newly mounted directory the root (or parent) directory. This you do by running the chroot command as follows:

# chroot /mnt/sysimage
# _

Now you are in the shell with respect to the parent directory which is the linux partition on your harddisk.

From here, the steps needed depends on which bootloader you are using. You have to have a fair idea what is the device node of your harddisk partition housing your MBR. In most cases, it is /dev/hda if you have an IDE harddisk. But if you have a SCSI harddisk, it will be /dev/sda.

Restoring GRUB

Execute the following command :

# grub-install /dev/hda

... to install GRUB boot loader on to your MBR. And then type exit to reboot the machine. Now your GRUB boot loader is fixed.

Restoring LILO

LILO stands for LInux LOader which was the boot loader used before GRUB was developed. It is fairly cryptic and is the default bootloader prior to and in RedHat 7.0 .Here you just type the command :

# /sbin/lilo

... to install the bootloader on to the MBR.

If you don't have a Fedora CD, then you need not despair. You can also repair the boot loader using one of the numerous live CDs available.

what is Master boot record and LILO ?

noreply@blogger.com (Arun Tom) — Wed, 06 Jul 2011 18:02:00 +0000

Master boot record and LILO

What is the master boot record (MBR) and why does LILO erase the old boot loader? Every hard drive has a
top space called the MBR where the BIOS will try to load an operating system. Every system has its own
loader. DOS has DOS-MBR, Windows NT has the NTLDR and Linux has LILO.
When you install LILO, you can install it in the MBR or in a boot record for the Linux partition. If you want
to keep your current boot loader, you can select the Linux partition, and make sure it is the active partition in
fdisk. This way you will be able to boot to LILO, and then boot the old loader from the MBR.
If you plan on only using Linux on your system, you can tell LILO to boot right into Linux and not display a
"boot:" prompt, and you can install it in the MBR.

Master boot record (MBR) is a type of boot sector popularized by the IBM Personal Computer.It consists of a sequence of 512 bytes located at the first sector of a data storage device such as a hard disk. MBRs are usually placed on storage devices intended for use with IBM PC-compatible systems.

The MBR may be used for one or more of the following:

Holding a partition table which describes the partitions of a storage device. In this context the boot sector may also be known as a partition sector.
Bootstrapping an operating system. The BIOS built into a PC-compatible computer loads the MBR from the storage device and passes execution to machine code instructions at the beginning of the MBR.
Uniquely identifying individual disk media, with a 32-bit disk signature, even though it may never be used by the operating system.

The Linux boot prompt

noreply@blogger.com (Arun Tom) — Wed, 06 Jul 2011 17:47:00 +0000

The Linux system uses a program called LILO to boot itself.
This is the LInux LOader, and will load a kernel
and can pass various parameters. This is what the "boot:" prompt is for.
At the "boot:" prompt, you can enter a lot of parameters. You can send parameters to drivers like the ethernet
driver, telling it at which IRQ the ethernet card is located, or you can pass parameters to the kernel, like
memory size or what to do in a panic. Reading the LILO manual will tell you all of the nice things LILO can
be used for.
Note that for device drivers compiled as modules, you need to pass values when you load these drivers, and
not on the "boot:" prompt.

Installing Linux with no CD-ROM drive or modem

noreply@blogger.com (Arun Tom) — Wed, 06 Jul 2011 17:30:00 +0000

Most Linux distributions come on a CD-ROM. You can also download them from an FTP site, but that
requires an Internet connection. What if you have a system with no CD-ROM drive or Internet connection,
like an old 486 laptop? The trick here is to have another desktop system with a CD-ROM drive, and a
null-modem serial cable.
I will show you how to do it with Slackware. It is also possible with most other Linux distributions. Insert the
Linux CD-ROM in the drive on the desktop and copy the A (base) and N (networking) packages on diskettes.
You need at least those in order to use a serial cable to transfer the rest of the packages.
Now you need to enable NFS networking on the desktop, and allow the laptop to connect. You can give a
temporary IP address to the laptop, like 192.168.1.11 that you need to add to your /etc/exports file on your
desktop.

To link the two systems together, this is what you need to type on the laptop:

/usr/sbin/pppd -detach crtscts lock 192.168.1.11:192.168.1.10 /dev/ttyS1 115200

And this on the PC:

/usr/sbin/pppd -detach crtscts lock 192.168.1.10:192.168.1.11 /dev/ttyS1 115200

This is assuming the cable is linked to ttyS1 (COM2) on both systems.
With NFS, you can mount the CD-ROM drive remotely and tell the installation program to use a specific
path to install the remaining packages.

Mount the CD-ROM with a command like this:

mount -tnfs 192.168.1.10:/cdrom /mnt

Then run the installation program:
setup

and enter the new path for the packages files.

How To Create A linux Boot CD

noreply@blogger.com (Arun Tom) — Tue, 05 Jul 2011 14:39:00 +0000

The kernel in Fedora Core 2 and higher is too big to fit on a floppy disk, so you'll have to create a boot CD instead. Here are the steps.

1. Each installed kernel has a dedicated subdirectory for its modules in the /lib/modules directory. Get a listing of this directory. Here there are two installed kernels; versions 2.6.5-1.358custom and 2.6.8-1.521.

[root@bigboy tmp]# ls /lib/modules/
2.6.5-1.358custom  2.6.8-1.521
[root@bigboy tmp]#

2. Select the desired kernel and use the mkbootdisk command to create a CD ISO image named /tmp/boot.iso of one of the kernels, in this case 2.6.8-1.521:

[root@bigboy tmp]# mkbootdisk --iso --device /tmp/boot.iso \
                     2.6.8-1.521

3. Burn a CD using the image. This creates a boot CD with the specified kernel, named vmlinuz, and a scaled-down version of the grub.conf configuration file named isolinux.cfg, both located in the isolinux subdirectory of the CD. This example mounts the newly created CD-ROM and takes a look at the isolinux.cfg file to confirm that everything is okay.

[root@bigboy tmp]# mount /mnt/cdrom
[root@bigboy tmp]# ls /mnt/cdrom/isolinux/
boot.cat  boot.msg  initrd.img  isolinux.bin  isolinux.cfg   TRANS.TBL  vmlinuz
[root@bigboy tmp]# cat /mnt/cdrom/isolinux/isolinux.cfg
default linux
prompt 1
display boot.msg
timeout 100
label linux
        kernel vmlinuz
        append initrd=initrd.img ro  root=/dev/hda2
[root@bigboy tmp]#

When you reboot your system with the CD, the boot process automatically attempts to access your files in the /root partition and boot normally. The only difference being that the kernel used is on the CD.

Updating The Kernel Using RPMs

It is also possible to install a new standardized kernel from an RPM file. As you can see, it is much simpler than creating a customized one.

To create an additional kernel using RPMs, use the command

[root@bigboy tmp]# rpm -ivh kernel-file.rpm

To replace an existing kernel using RPMs, you need only one line

[root@bigboy tmp]# rpm -Uvh kernel-file.rpm

Conclusion

Building a customized Linux kernel is probably something that most systems administrators won't do themselves. The risk of having a kernel that may fail in some unpredictable way is higher when you modify it, and, therefore, many system administrators hire experts to do the work for them. After reading this chapter, at least you will have an idea of what is going on when the expert arrives, which can help considerably when things don't go according to plan.

Modifying the Linux Kernel to Improve Performance

noreply@blogger.com (Arun Tom) — Tue, 05 Jul 2011 14:34:00 +0000

Introduction

Like a government that rules a nation and all its provinces, the Linux kernel is the central program that not only governs how programs interact with one another, but also provides the guidelines on how they should use the computer's core infrastructure, such as memory, disks, and other input/output (I/O) devices for the user's benefit.

Linux drivers, the programs that manage each I/O device, are the staff that keeps all the government departments running. Continuing with the analogy, the more departments you make the kernel manage, the slower Linux becomes. Large kernels also reduce the amount of memory left over for user applications. These may then be forced to juggle their memory needs between RAM and the much slower swap partitions of disk drives, causing the whole system to become sluggish.

The Fedora installation CDs have a variety of kernel RPMs, and the installation process autodetects the one best suited to your needs. For this reason, the Fedora Linux kernel installed on your system is probably sufficient. The installation process chooses one of several prebuilt kernel types depending on the type of CPU and configuration you intend to use (Table 33-1).

Kernels Found On Fedora Installation CDs

Processor Type	Configuration
i586	Single processor
i586	Multiprocessor (SMP)
i686	Single processor
i686	Multiprocessor (SMP)

The Pros And Cons Of Kernel Upgrades

Despite this best fit installation, you may want to rebuild the kernel at times. For example, there is no installation RPM for multiprocessor systems with large amounts of memory. You may also want to experiment in making a high-speed Linux router without support for SCSI, USB, Bluetooth, and sound but with support for a few NIC drivers, an IDE hard drive, and a basic VGA console. This would require a kernel rebuild.

Rebuilding the kernel in a small business environment is usually unnecessary. If your system starts to slow down and you can't afford to replace hardware or are unable to add more RAM, however, you may want to tune the kernel by making it support only necessary functions or updating built-in parameters to make it perform better. Sometimes new features within the new kernel are highly desirable; for example, the version 2.6 kernel has much more efficient data handling capabilities than the older version 2.4, providing new life for old hardware.

Kernel tuning on a production server shouldn't be taken lightly, because the wrong parameters could cause your system to fail to boot, software to malfunction, or hardware peripherals to become unavailable. Always practice on a test system and keep a backup copy of your old kernel. Whenever possible, hire a consultant with kernel experience to help, and use this chapter and other references as a guide to prepare you for what to expect.

This chapter provides only an overview of the steps to take. It won't make you an expert, but it will expose you to the general process and provide greater confidence when you need to research the task with a specialized guide.

The Kernel Sources Package

You will need to install the kernel source code on your system prior to modifying your kernel. As of Fedora Core 3, the kernel sources come as a source RPM package that matches the version of the kernel you are running. In Fedora Core 2 and earlier, the Kernel sources came as a generic RPM package called kernel-source, the installation of which is covered in Appendix III, "Fedora Version Differences".

The newer method is more complicated as it requires a number of post installation steps. Though the process is well documented in the release notes section of the Fedora website (http://fedora.redhat.com/docs/release-notes/) there are some clarifications that are needed. These are explained in the following section.

Installing Kernel Sources

The installation process for the kernel sources is long, but not very complicated. Here is how it's done:

1. Determine the version of your kernel with the uname command. In this case it is version 2.6.14-1.1644.

[root@bigboy tmp]# uname -r
2.6.14-1.1644_FC4smp
[root@bigboy tmp]#

2. Visit your favorite Fedora operating system download mirror and get the corresponding source RPM package. If you are running the original version of the kernel that came with your installation discs, then the sources will be located in the /core/<version>/i386/os/SRPMS/ directory. If the kernel has been updated using yum or some other method, the sources will be located in the /core/updates/<version>/SRPMS/ directory. In this example the sources of an updated Core 4 kernel is downloaded from the /core/updates/4/SRPMS/ directory of http://download.fedora.redhat.com using wget.

[root@bigboy tmp]# wget
http://download.fedora.redhat.com/pub/fedora/linux/core/updates/4/SRPMS/kernel-2.6.14-1.1644_FC4.src.rpm
--15:32:22-- 
http://download.fedora.redhat.com/pub/fedora/linux/core/updates/4/SRPMS/kernel-2.6.14-1.1644_FC4.src.rpm
           => `kernel-2.6.14-1.1644_FC4.src.rpm'
Resolving download.fedora.redhat.com... 66.187.224.20,
209.132.176.20, 209.132.176.220, ...
Connecting to
download.fedora.redhat.com|66.187.224.20|:80...
connected.
HTTP request sent, awaiting response... 200 OK
Length: 40,454,218 (39M) [application/x-rpm]

100%[=========================>] 40,454,218   862.89K/s    ETA 00:00

15:33:10 (842.22 KB/s) -
`kernel-2.6.14-1.1644_FC4.src.rpm' saved
[40454218/40454218]

[root@bigboy tmp]#

3. Install the contents of the RPM file into the /usr/src/redhat/SOURCES and /usr/src/redhat/SPECS directories using the rpm command.

[root@bigboy tmp]# rpm -Uvh kernel-2.6.14-1.1644_FC4.src.rpm 
   1:kernel                 ########################################### [100%]
[root@bigboy tmp]#

4. The kernel source directory tree will have to be created next. Enter the /usr/src/redhat/SPECS directory and create the tree using the rpmbuild command with the -bp option.

[root@bigboy tmp]# cd /usr/src/redhat/SPECS
[root@bigboy SPECS]# ls
kernel-2.6.spec
[root@bigboy SPECS]# rpmbuild -bp --target $(arch) kernel-2.6.spec
Building target platforms: i686
Building for target i686
Executing(%prep): /bin/sh -e /var/tmp/rpm-tmp.44004
+ umask 022
+ cd /usr/src/redhat/BUILD
...
...
...
removed `./init/Kconfig.orig'
removed `./init/main.c.orig'
+ find . -name '*~' -exec rm -fv '{}' ';'
+ exit 0
[root@bigboy SPECS]#

5. The tree has now been created in the /usr/src/redhat/BUILD/kernel-<version> directory. You can link, move or copy this directory to become /usr/src/linux depending on your needs and the likelihood of you compiling multiple kernel versions in future. In this case, the tree is moved and then linked.

[root@bigboy SPECS]# cd /usr/src/redhat/BUILD/kernel-2.6.14/
[root@bigboy kernel-2.6.14]# ls
linux-2.6.14  vanilla
[root@bigboy kernel-2.6.14]# mv linux-2.6.14 /usr/src/
[root@bigboy kernel-2.6.14]# cd /usr/src
[root@bigboy src]# ln -s ./linux-2.6.14 linux
[root@bigboy src]# ls
kernels  linux  linux-2.6.14  redhat
[root@bigboy src]#

6. The configuration files for specific kernels shipped in Fedora Core will be located in the configs/ directory. In this case the uname -a command is used to determine the systems CPU type (686) and the kernel type (SMP, Symmetrical Multi Processor), and the relevant configuration file is then copied to become the new /usr/src/linux/.config file to be used during the kernel compilation.

[root@bigboy src]# cd /usr/src/linux
[root@bigboy linux]# uname -a
Linux bigboy.my-web-site.org 2.6.14-1.1644_FC4smp #1 SMP
Sun Nov 27 03:39:31 EST 2005 i686 i686 i386 GNU/Linux
[root@bigboy linux]# cp configs/kernel-2.6.14-i686-smp.config .config
cp: overwrite `.config'? y
[root@bigboy linux]#

7. You can also automatically copy the correct file from the /usr/src/linux/configs/ directory to /usr/src/linux/.config using the make oldconfig command.

[root@bigboy linux]# cd /usr/src/linux
[root@bigboy linux]# make oldconfig

You should now be ready to compile a customized kernel at your leisure, but first I'll discuss Kernel modules.

Kernel Modules

Over the years the Linux kernel has evolved, in the past device drivers were included as part of this core program, whereas now they are loaded on demand as modules.

Reasons For Kernel Modules

There are a number of advantages to this new architecture:

Updates to a driver, such as a USB controller module, don't require a complete recompilation of the kernel; just the module itself needs recompiling. This reduces the likelihood of errors and ensures that the good, working base kernel remains unchanged.
An error in a device driver is less likely to cause a fault that prevents your system from booting. A faulty device driver can be prevented from loading at boot time by commenting out its entry in the /etc/modprobe.conf file, or by using the rmmod command after boot time. In the past, the kernel would have to be recompiled.
Updates to a driver don't require a reboot either, just the unloading of the old and reloading of the new module.
You can add new devices to your system without requiring a new kernel, only the new module driver is needed. This adds a great deal of flexibility without a lot of systems administrator overhead.

There are some drivers that will always need to be compiled into the kernel to make sure your system boots correctly. For example, routines for basic system functions used in reading and writing files, are an indispensable integrated part of any kernel.

Loadable kernel modules now include device drivers to manage various types of filesystems, network cards, and terminal devices to name a few. As they work so closely with the kernel, the modules need to be compiled specifically for the kernel they are intended to support. The kernel always looks for modules for its version number in the /lib/modules/<kernel version> directory and permanently loads them into RAM memory for faster access. Some critical modules are loaded automatically, others need to be specified in the /etc/modprobe.conf file.

The kernel recompilation process provides you with the option of compiling only the loadable modules. I won't specifically cover this, but simultaneous recompilation of all modules will be covered as part of the overall recompilation of your kernel.

How Kernel Modules Load When Booting

One question that must come to mind is "How does the kernel boot if the disk controller modules reside on a filesystem that isn't mounted yet?"

As stated in Chapter 7, "The Linux Boot Process", the GRUB boot loader resides on its own dedicated partition and uses the /boot/grub/grub.conf file to determine the valid kernels and their locations. The grub.conf file not only defines the available kernels, but also the location of the root partition and an associated ramdisk image that is automatically loaded into memory and that contains just enough modules to get the root filesystem mounted.

Note: In Fedora Linux, the /boot/grub/grub.conf file can also be referenced via the symbolic link file named /etc/grub.conf.

Modules And The grub.conf File

In this example of the /boot/grub/grub.conf file, the kernel in the /boot directory is named vmlinuz-2.6.8-1.521, its RAM disk image file is named initrd-2.6.8-1.521.img, and the root partition is (hd0,0).

#
# File: /boot/grub/grub.conf
#
default=0
timeout=10
splashimage=(hd0,0)/grub/splash.xpm.gz
title Fedora Core (2.6.8-1.521)
        root (hd0,0)
        kernel /vmlinuz-2.6.8-1.521 ro root=LABEL=/
        initrd /initrd-2.6.8-1.521.img

The .img file is created as part of the kernel compilation process, but can also be created on demand with the mkinitrd command.

The (hd0,0).disk definition may seem strange, but there is a file that maps the GRUB device nomenclature to that expected by Linux in the /boot/grub/device.map file.

#
# File: /boot/grub/device.map
#
(fd0)     /dev/fd0
(hd0)     /dev/hda

During the next phase of the boot process, the loaded kernel executes the init program located on the RAM disk, which mounts the root filesystem and loads the remaining modules defined in the /etc/modprobe.conf file before continuing with the rest of the startup process.

Loading Kernel Modules On Demand

It is possible to load add-on modules located under the /lib/modules/<kernel version> directory with the modprobe command. For example, the iptables firewall application installs kernel modules that it uses to execute NAT and pass FTP traffic. In this example: these modules are loaded with the modprobe command with the aid of the /etc/rc.local script.

#
# File: /etc/rc.local
#
# Load iptables FTP module when required
modprobe ip_conntrack_ftp

# Load iptables NAT module when required
modprobe iptable_nat

Kernel module drivers that are referenced by the operating system by their device aliases are placed in the /etc/modprobe.conf file and are loaded automatically at boot time. In the example, you can see that devices eth1 and eth0 use the natsemi and orinoco_pci drivers respectively.

#
# /etc/modprobe.conf
#
alias eth1 natsemi
alias eth0 orinoco_pci

Linux has a number of commands to help you with modules. The lsmod command lists all the ones loaded. In the example, you can see that iptables, NFS, and the Orinoco drivers are all kernel modules. You can use the modprobe command to load and unload modules or use the insmod and rmmod commands. See the man pages for details.

[root@bigboy tmp]# lsmod
Module                  Size  Used by
...
...
iptable_filter          2048  0
ip_tables              13440  1 iptable_filter
...
...
exportfs                4224  1 nfsd
nfs                   142912  0
lockd                  47944  3 nfsd,nfs
autofs4                10624  1
sunrpc                101064  20 nfsd,nfs,lockd
...
...
natsemi                18016  0
orinoco_pci             4876  0
orinoco                31500  1 orinoco_pci
hermes                  6528  2 orinoco_pci,orinoco
...
...
[root@bigboy tmp]#

Finally, when in doubt about a device driver, try using the lspci command to take a look at the devices that use your PCI expansion bus. Here you can see that the natsemi module listed in the lsmod command has a high probability of belonging to the 01:08.0 Ethernet controller: device made by National Semiconductor.

[root@bigboy tmp]# lspci
...
...
01:07.0 Network controller: Intersil Corporation Prism 2.5 Wavelan chipset (rev 01)
01:08.0 Ethernet controller: National Semiconductor Corporation DP83815 (MacPhyter) Ethernet Controller
01:0c.0 Ethernet controller: 3Com Corporation 3c905C-TX/TX-M [Tornado] (rev 78)
[root@bigboy tmp]#

Creating A Custom Kernel

The installation of the kernel sources creates a file called README in the /usr/src/linux directory that briefly outlines the steps needed to create a new kernel. Take a look at a more detailed explanation of the required steps.

Make Sure Your Source Files Are In Order

Cleaning up the various source files is the first step. This isn't so important for a first time rebuild, but it is vital for subsequent attempts. You use the make mrproper command to do this; it must be executed in the Linux kernel version's subdirectory located under /usr/src. In this case, the subdirectory's name is /usr/src/linux-2.6.5-1.358.

[root@bigboy tmp]# cd /usr/src/linux
[root@bigboy linux]# make mrproper
...
...
...
[root@bigboy linux]#

The ".config" File

You next need to run scripts to create a kernel configuration file called /usr/src/linux/.config. This file lists all the kernel options you wish to use.

Backup Your Configuration

The .config file won't exist if you've never created a custom kernel on your system before, but fortunately, RedHat stores a number of default .config files in the /usr/src/linux/configs directory. You can automatically copy the .config file that matches your installed kernel by running the make oldconfig command in the /usr/src/linux directory.

[root@bigboy tmp]# cd /usr/src/linux
[root@bigboy linux]# ls .config
ls: .config: No such file or directory
[root@bigboy linux]# make oldconfig
...
...
...
[root@bigboy linux]#

If you've created a custom kernel before, the .config file that the previous custom kernel build used will already exist. Copy it to a safe location before proceeding.

Customizing The ".config" File

Table 33-2 lists three commands that you can run in the /usr/src/linux directory to update the .config file.

Table 33-2 Scripts For Modifying The .config File

Command	Description
make config	Text based utility that prompts you line by line. This method can become laborious.
make menuconfig	Text menu based utility.
make gconfig	X-Windows GUI based utility.

Kernel Option Choices

Kernel Option Choice	Description
M	The kernel will load the drivers for this option on an as needed basis. Only the code required to load the driver on demand will be included in the kernel.
Y	Include all the code for the drivers needed for this option into the kernel itself. This will generally make the kernel larger and slower but will make it more self sufficient. The "Y" option is frequently used in cases in which a stripped down kernel is one of the only programs Linux will run, such as purpose built home firewall appliances you can buy in a store. There is a limit to the overall size of a kernel. It will fail to compile if you select parameters that will make it too big.
N	Don't make the kernel support this option at all.

Kernel Configuration Options

Option	Description
Code maturity level options	Determines whether Linux prompts you for certain types of development code or drivers.
Loadable module support	Support for loadable modules versus a monolithic kernel. Most of the remaining kernel options use loadable modules by default. It is best to leave this alone in most cases.
Processor type and features	SMP, Large memory, BIOS and CPU type settings.
General setup	Support for power management, networking, and systems buses such as PCI, PCMCIA, EISA, ISA
Memory technology devices	Linux subsystem for memory devices, especially Flash devices
Parallel port support	Self explanatory
Plug and Play configuration	Support of the automatic new hardware detection method called plug and play
Block devices	Support for a number of parallel-port-based and ATAPI type devices. Support for your loopback interface and RAM disks can be found here too.
Multidevice support (RAID, LVM)	Support for RAID, 0, 1, and 5, as well as LVM.
Cryptography support (CryptoAPI)	Support for various types of encryption
Networking options	TCP/IP, DECnet, Appletalk, IPX, ATM/LANE
Telephony support	Support for voice to data I/O cards
ATA/IDE/MFM/RLL support	Support for a variety of disk controller chipsets
SCSI support	Support for a variety of disk controller chipsets. Also sets limits on the maximum number of supported SCSI disks and CDROMs.
Fusion MPT support	High speed SCSI chipset support.
I2O device support	Support for specialized Intelligent I/O cards
Network device support	Support for Ethernet, Fibre Channel, FDDI, SLIP, PPP, ARCnet, Token Ring, ATM, PCMCIA networking, and specialized WAN cards.
Amateur Radio support	Support for packet radio
IrDA subsystem support	Infrared wireless network support
ISDN subsystem	Support for ISDN
Old CD-ROM drivers (not SCSI, not IDE)	Support for non-SCSI, non-IDE, non ATAPI CDROMs
Input core support	Keyboard, mouse, and joystick support in addition to the default VGA resolution.
Character devices	Support for virtual terminals and various serial cards for modems, joysticks and basic parallel port printing.
Multimedia devices	Streaming video and radio I/O card support
Crypto Hardware support	Web-based SSL hardware accelerator card support
Console drivers	Support for various console video cards
Filesystems	Support for all the various filesystems and strangely, the native languages supported by Linux.
Sound	Support for a variety of sound cards
USB support	Support for a variety of USB devices
Additional device driver support	Miscellaneous driver support
Bluetooth support	Support for a variety of Bluetooth devices
Kernel hacking	Support for detailed error messages for persons writing device drivers

Configure Dependencies

As I mentioned before, the .config file you just created lists the options you'll need in your kernel. In version 2.4 of the kernel and older, the make dep command was needed at this step to prepare the needed source files for compiling. This step has been eliminated as of version 2.6 of the kernel.

Edit The Makefile To Give The Kernel A Unique Name

Edit the file Makefile and change the line "EXTRAVERSION =" to create a unique suffix at the end of the default name of the kernel.

For example, if your current kernel version is 2.6.5-1.358, and your EXTRAVERSION is set to -6-new, your new additional kernel will have the name vmlinuz-2.6.5-6-new.

Remember to change this for each new version of the kernel you create.

Compile A New Kernel

You can now use the make command to create a compressed version of your new kernel and its companion .img RAM disk file. This could take several hours on a 386 or 486 system. It will take about 20 minutes on a 400MHz Celeron.

[root@bigboy linux-2.6.5-1.358]# make 
...
...
...
[root@bigboy linux-2.6.5-1.358]#

Note: In older versions of Fedora the command to do this would have been make bzImage.

Build The Kernel's Modules

You can now use the make modules_install command to copy all the modules created in the previous step to the conventional module locations.

[root@bigboy linux]# make modules_install
...
...
...
[root@bigboy linux]#

Note: In versions of Fedora before Core 3, this was a two step process. The make modules command would compile the modules, but locate them within the Linux kernel source directory tree under the directory /usr/src/. The make modules_install command would then relocates them to where they should finally reside under the /lib/modules/<kernel version> directory.

Copy The New Kernel To The /boot Partition

The kernel and the .img you just created needs to be copied to the /boot partition where all your systems active kernel files normally reside. This is done with the make install command.

This partition has a default size of 100MB, which is enough to hold a number of kernels. You may have to delete some older kernels to create enough space.

[root@bigboy linux]# make install
...
...
...
[root@bigboy linux]#

Here you can see that the new kernel vmlinuz-2.6.5-1.358-new is installed in the /boot directory.

[root@bigboy linux]# ls -l /boot/vmlinuz*
lrwxrwxrwx 1 root root       22 Nov 28 01:20 /boot/vmlinuz -> vmlinuz-2.6.5-1.358-new
-rw-r--r-- 1 root root  1122363 Feb 27  2003 /boot/vmlinuz-2.6.5-1.358
-rw-r--r-- 1 root root  1122291 Nov 28 01:20 /boot/vmlinuz-2.6.5-1.358-new
[root@bigboy linux]#

Updating GRUB

You should now update your /etc/grub.conf file to include an option to boot the new kernel. The make install command does this for you automatically.

In this example, default is set to 1, which means the system boots the second kernel entry, which happens to be that of the original kernel 2.6.5-1.358. You can set this value to 0, which makes it boot your newly compiled kernel (the first entry).

default=1
timeout=10
splashimage=(hd0,0)/grub/splash.xpm.gz
title Red Hat Linux (2.6.5-1.358-new)
        root (hd0,0)
        kernel /vmlinuz-2.6.5-1.358-new ro root=LABEL=/
        initrd /initrd-2.6.5-1.358-new.img
title Red Hat Linux (2.6.5-1.358)
        root (hd0,0)
        kernel /vmlinuz-2.6.5-1.358 ro root=LABEL=/
        initrd /initrd-2.6.5-1.358.img

Kernel Crash Recovery

Sometimes the new default kernel will fail to boot or work correctly with the new kernel. A simple way of recovering from this is to reboot your system, selecting the old version of the kernel from the Fedora splash screen. Once the system has booted with this stable version, edit the grub.conf file and set the default parameter to point to the older version instead. If this fails, you may want to boot from a CD with the original kernel. You can then try to either reinstall a good kernel RPM or rebuild the failed one over again after fixing the configuration problem that caused the trouble in the first place.

*//

Linux or GNU/Linux ?

noreply@blogger.com (Arun Tom) — Tue, 05 Jul 2011 12:42:00 +0000

You've probably noticed that Linux as an operating system is referred to in some cases as "Linux" and in others as "GNU/Linux." The reason behind this is that Linux is the kernel of an operating system. The wide range of applications that make the operating system useful are the GNU software. For example, the windowing system, compiler, variety of shells, development tools, editors, utilities, and other applications exist outside of the kernel, many of which are GNU software. For this reason, many consider "GNU/Linux" a more appropriate name for the operating system, while "Linux" is appropriate when referring to just the kernel.

Anatomy of the Linux kernel

noreply@blogger.com (Arun Tom) — Tue, 05 Jul 2011 12:39:00 +0000

History and architectural decomposition

Given that the goal of this article is to introduce you to the Linux kernel and explore its architecture and major components, let's start with a short tour of Linux kernel history, then look at the Linux kernel architecture from 30,000 feet, and, finally, examine its major subsystems. The Linux kernel is over six million lines of code, so this introduction is not exhaustive. Use the pointers to more content to dig in further.

A short tour of Linux history

While Linux is arguably the most popular open source operating system, its history is actually quite short considering the timeline of operating systems. In the early days of computing, programmers developed on the bare hardware in the hardware's language. The lack of an operating system meant that only one application (and one user) could use the large and expensive device at a time. Early operating systems were developed in the 1950s to provide a simpler development experience. Examples include the General Motors Operating System (GMOS) developed for the IBM 701 and the FORTRAN Monitor System (FMS) developed by North American Aviation for the IBM 709.

In the 1960s, Massachusetts Institute of Technology (MIT) and a host of companies developed an experimental operating system called Multics (or Multiplexed Information and Computing Service) for the GE-645. One of the developers of this operating system, AT&T, dropped out of Multics and developed their own operating system in 1970 called Unics. Along with this operating system was the C language, for which C was developed and then rewritten to make operating system development portable.

Twenty years later, Andrew Tanenbaum created a microkernel version of UNIX®, called MINIX (for minimal UNIX), that ran on small personal computers. This open source operating system inspired Linus Torvalds' initial development of Linux in the early 1990s (see Figure 1).

Figure 1. Short history of major Linux kernel releases

Linux quickly evolved from a single-person project to a world-wide development project involving thousands of developers. One of the most important decisions for Linux was its adoption of the GNU General Public License (GPL). Under the GPL, the Linux kernel was protected from commercial exploitation, and it also benefited from the user-space development of the GNU project (of Richard Stallman, whose source dwarfs that of the Linux kernel). This allowed useful applications such as the GNU Compiler Collection (GCC) and various shell support.

Introduction to the Linux kernel

Now on to a high-altitude look at the GNU/Linux operating system architecture. You can think about an operating system from two levels, as shown in Figure 2.

Figure 2. The fundamental architecture of the GNU/Linux operating system

At the top is the user, or application, space. This is where the user applications are executed. Below the user space is the kernel space. Here, the Linux kernel exists.

There is also the GNU C Library (glibc). This provides the system call interface that connects to the kernel and provides the mechanism to transition between the user-space application and the kernel. This is important because the kernel and user application occupy different protected address spaces. And while each user-space process occupies its own virtual address space, the kernel occupies a single address space. For more information, see the links in the Resources section.

The Linux kernel can be further divided into three gross levels. At the top is the system call interface, which implements the basic functions such as read and write. Below the system call interface is the kernel code, which can be more accurately defined as the architecture-independent kernel code. This code is common to all of the processor architectures supported by Linux. Below this is the architecture-dependent code, which forms what is more commonly called a BSP (Board Support Package). This code serves as the processor and platform-specific code for the given architecture.

Properties of the Linux kernel

When discussing architecture of a large and complex system, you can view the system from many perspectives. One goal of an architectural decomposition is to provide a way to better understand the source, and that's what we'll do here.

The Linux kernel implements a number of important architectural attributes. At a high level, and at lower levels, the kernel is layered into a number of distinct subsystems. Linux can also be considered monolithic because it lumps all of the basic services into the kernel. This differs from a microkernel architecture where the kernel provides basic services such as communication, I/O, and memory and process management, and more specific services are plugged in to the microkernel layer. Each has its own advantages, but I'll steer clear of that debate.

Over time, the Linux kernel has become efficient in terms of both memory and CPU usage, as well as extremely stable. But the most interesting aspect of Linux, given its size and complexity, is its portability. Linux can be compiled to run on a huge number of processors and platforms with different architectural constraints and needs. One example is the ability for Linux to run on a process with a memory management unit (MMU), as well as those that provide no MMU. The uClinux port of the Linux kernel provides for non-MMU support. See the Resources section for more details.

Major subsystems of the Linux kernel

Now let's look at some of the major components of the Linux kernel using the breakdown shown in Figure 3 as a guide.

Figure 3. One architectural perspective of the Linux kernel

System call interface

The SCI is a thin layer that provides the means to perform function calls from user space into the kernel. As discussed previously, this interface can be architecture dependent, even within the same processor family. The SCI is actually an interesting function-call multiplexing and demultiplexing service. You can find the SCI implementation in ./linux/kernel, as well as architecture-dependent portions in ./linux/arch. More details for this component are available in the Resources section.

Process management

Process management is focused on the execution of processes. In the kernel, these are called threads and represent an individual virtualization of the processor (thread code, data, stack, and CPU registers). In user space, the term process is typically used, though the Linux implementation does not separate the two concepts (processes and threads). The kernel provides an application program interface (API) through the SCI to create a new process (fork, exec, or Portable Operating System Interface [POSIX] functions), stop a process (kill, exit), and communicate and synchronize between them (signal, or POSIX mechanisms).

Also in process management is the need to share the CPU between the active threads. The kernel implements a novel scheduling algorithm that operates in constant time, regardless of the number of threads vying for the CPU. This is called the O(1) scheduler, denoting that the same amount of time is taken to schedule one thread as it is to schedule many. The O(1) scheduler also supports multiple processors (called Symmetric MultiProcessing, or SMP). You can find the process management sources in ./linux/kernel and architecture-dependent sources in ./linux/arch). You can learn more about this algorithm in the Resources section.

Memory management

Another important resource that's managed by the kernel is memory. For efficiency, given the way that the hardware manages virtual memory, memory is managed in what are called pages (4KB in size for most architectures). Linux includes the means to manage the available memory, as well as the hardware mechanisms for physical and virtual mappings.

But memory management is much more than managing 4KB buffers. Linux provides abstractions over 4KB buffers, such as the slab allocator. This memory management scheme uses 4KB buffers as its base, but then allocates structures from within, keeping track of which pages are full, partially used, and empty. This allows the scheme to dynamically grow and shrink based on the needs of the greater system.

Supporting multiple users of memory, there are times when the available memory can be exhausted. For this reason, pages can be moved out of memory and onto the disk. This process is called swapping because the pages are swapped from memory onto the hard disk. You can find the memory management sources in ./linux/mm.

Virtual file system

The virtual file system (VFS) is an interesting aspect of the Linux kernel because it provides a common interface abstraction for file systems. The VFS provides a switching layer between the SCI and the file systems supported by the kernel (see Figure 4).

Figure 4. The VFS provides a switching fabric between users and file systems

At the top of the VFS is a common API abstraction of functions such as open, close, read, and write. At the bottom of the VFS are the file system abstractions that define how the upper-layer functions are implemented. These are plug-ins for the given file system (of which over 50 exist). You can find the file system sources in ./linux/fs.

Below the file system layer is the buffer cache, which provides a common set of functions to the file system layer (independent of any particular file system). This caching layer optimizes access to the physical devices by keeping data around for a short time (or speculatively read ahead so that the data is available when needed). Below the buffer cache are the device drivers, which implement the interface for the particular physical device.

Network stack

The network stack, by design, follows a layered architecture modeled after the protocols themselves. Recall that the Internet Protocol (IP) is the core network layer protocol that sits below the transport protocol (most commonly the Transmission Control Protocol, or TCP). Above TCP is the sockets layer, which is invoked through the SCI.

The sockets layer is the standard API to the networking subsystem and provides a user interface to a variety of networking protocols. From raw frame access to IP protocol data units (PDUs) and up to TCP and the User Datagram Protocol (UDP), the sockets layer provides a standardized way to manage connections and move data between endpoints. You can find the networking sources in the kernel at ./linux/net.

Device drivers

The vast majority of the source code in the Linux kernel exists in device drivers that make a particular hardware device usable. The Linux source tree provides a drivers subdirectory that is further divided by the various devices that are supported, such as Bluetooth, I2C, serial, and so on. You can find the device driver sources in ./linux/drivers.

Architecture-dependent code

While much of Linux is independent of the architecture on which it runs, there are elements that must consider the architecture for normal operation and for efficiency. The ./linux/arch subdirectory defines the architecture-dependent portion of the kernel source contained in a number of subdirectories that are specific to the architecture (collectively forming the BSP). For a typical desktop, the i386 directory is used. Each architecture subdirectory contains a number of other subdirectories that focus on a particular aspect of the kernel, such as boot, kernel, memory management, and others. You can find the architecture-dependent code in ./linux/arch.

Interesting features of the Linux kernel

If the portability and efficiency of the Linux kernel weren't enough, it provides some other features that could not be classified in the previous decomposition.

Linux, being a production operating system and open source, is a great test bed for new protocols and advancements of those protocols. Linux supports a large number of networking protocols, including the typical TCP/IP, and also extension for high-speed networking (greater than 1 Gigabit Ethernet [GbE] and 10 GbE). Linux also supports protocols such as the Stream Control Transmission Protocol (SCTP), which provides many advanced features above TCP (as a replacement transport level protocol).

Linux is also a dynamic kernel, supporting the addition and removal of software components on the fly. These are called dynamically loadable kernel modules, and they can be inserted at boot when they're needed (when a particular device is found requiring the module) or at any time by the user.

A recent advancement of Linux is its use as an operating system for other operating systems (called a hypervisor). Recently, a modification to the kernel was made called the Kernel-based Virtual Machine (KVM). This modification enabled a new interface to user space that allows other operating systems to run above the KVM-enabled kernel. In addition to running another instance of Linux, Microsoft® Windows® can also be virtualized. The only constraint is that the underlying processor must support the new virtualization instructions. See the Resources section for more information.

Linux spearding Everywhere ?

noreply@blogger.com (Arun Tom) — Tue, 05 Jul 2011 12:21:00 +0000

It's quickly -- and usually quietly -- spreading into more and more services and devices, from e-mail to cars !

A revolution is quietly sweeping consumer technology, and its name is Linux. Burrowed deep within a widening range of products is the upstart operating system that's available free over the Internet and has been giving software giant Microsoft a run for its money in the area of desktop PCs.

Maybe you're not one of the open-source zealots who downloads and maintains a Linux desktop at home, all the while thumbing your nose at Bill Gates & Co. Maybe you don't even know what open source is. But chances are you're part of the uprising. And if you're not now, you will be soon.

Linux and other kinds of open-source software are cropping up in a host of everyday devices and technologies -- from the original TiVo digital video recorder to cell phones made by Motorola. Surf the Net much? (Since you're reading this, the answer is probably yes.) Open-source code is at the root of the increasingly popular FireFox browser. In fact, a big chunk of the Web itself is run by Linux and open-source software like the Apache Web Server and MySQL database.

What's behind all this? For starters, back-breaking technical work by engineers at individual companies and third-party Linux distributors such as MontaVista. Plus, groups like Open Source Development Labs (OSDL) and the CE Linux Forum that are marshaling resources to turn Linux, which traces its roots to the software running massive mainframe computers, into an operating system small enough to run on the tiniest phones and other devices.

For product manufacturers, the appeal of open source is clear. Unlike with corporate computing and PCs, there's little standardization in the software used in a lot of consumer electronics and other products. Even in the same company, legions of in-house engineers may write and support dozens of different architectures and operating systems. That's expensive and inefficient.

So in the case of simple operating systems -- say, the ones used in automotive anti lock brakes -- it makes sense to rely on an outside vendor, much like the way companies buy computer chips from a third party. Likewise, when it comes to phones and consumer devices that are becoming more like mini-computers, Linux can provide a more robust operating system with a built-in base of developers who can write games and other applications.

And you can't beat the price. Though Linux isn't free when you factor in training, service, and support, it's typically cheaper than alternatives.

Benefits or no, Linux still faces plenty of resistance. While many information-technology professionals have come to see open source as something respectable -- even indispensable, some consumers and makers of products for general use still view it as unreliable and hard to maintain, or even subversive. "It has this reputation as a hacker operating system, as something that geeks do in their spare time over the Internet," says Rick Merrit, editor at large of trade publication EE Times. "People want these devices to be very reliable."

Even Linus Torvalds, the Finnish programmer who started Linux in 1991, concedes that it faces big psychological barriers when it comes to phones and devices. "It will take them a while to be entirely comfortable with it," he said of consumer-electronics makers in an interview with Business Week Online late last year. "The same way it took the server-side companies a while to get used to the notion of open source a few years ago" .
So don't expect many device makers to promote products as running "Linux Inside" any time soon. Nor are open-source backers likely push for it. After all, one of the big advantages of Linux over Microsoft is that it doesn't require product branding, says William Weinberg of the OSDL. Until the Linux name gets too popular to be played down, open source may remain consumer companies' best-kept secret.

Ubuntu Software Centre 5.0 Designs Hint At Great Things to Come…

noreply@blogger.com (Arun Tom) — Tue, 05 Jul 2011 09:07:00 +0000

The Canonical design team are currently hard at work designing, testing, evaluating new layouts for the Ubuntu Software Centre version 5.0.

Their work so far has resulted in three highly impressive mock-ups of Ubuntu Software Store interfaces heavily featuring an aggregated set of features that are par-the-course for Application Stores across various platforms.

Revamp begins

Canonical’s Matthew Paul Thomas writing on the 2nd of June said: -

“…my design colleague Calum Pringle and I have been working on revising the design of Ubuntu Software Center. The objective is to make USC more interesting and attractive, both to Ubuntu users and to application developers.

For the competitor analysis, we looked at the Android Market, Mac and iPad App Stores, Blackberry App World, Bodega, and Chrome Web Store.

There are a few common elements we have noticed that we don’t have currently. Regardless of the final layout, it would be helpful to start thinking about how we might implement each of these.”

Some of these ideas include: -

Top rated applications
Context-specific recommendations
Top Rated
Most Popular
Preview videos
Multiple screenshots
Custom artwork for application screens

He continues: “For layout ideas, we’ve considered metaphors like a convenience store, supermarket, department store, vending machine, museum, art gallery, and even a sushi bar. “

These latter analogies play heavily in this current spate of designs. current mock-up designs, particularly in this ‘notice board’ one: -

Before you get too excited by the shiny shiny bling bling the mock-ups above are still subject to change, refinement, evaluation, user feedback and not all features shown will appear in Ubuntu 11.10.

But what you can get excited about is that the Ubuntu Software Centre – arguably one of Ubuntu’s strongest assets – is finally getting the level of design attention is so desperately needed.

Do you Know what Android is ?

noreply@blogger.com (Arun Tom) — Tue, 05 Jul 2011 05:14:00 +0000

Android is a software stack for mobile devices that includes an operating system, middleware and key applications. The Android SDK provides the tools and APIs necessary to begin developing applications on the Android platform using the Java programming language.

Features

Application framework enabling reuse and replacement of components
Dalvik virtual machine optimized for mobile devices
Integrated browser based on the open source WebKit engine
Optimized graphics powered by a custom 2D graphics library; 3D graphics based on the OpenGL ES 1.0 specification (hardware acceleration optional)
SQLite for structured data storage
Media support for common audio, video, and still image formats (MPEG4, H.264, MP3, AAC, AMR, JPG, PNG, GIF)
GSM Telephony (hardware dependent)
Bluetooth, EDGE, 3G, and WiFi (hardware dependent)
Camera, GPS, compass, and accelerometer (hardware dependent)
Rich development environment including a device emulator, tools for debugging, memory and performance profiling, and a plugin for the Eclipse IDE

Android Architecture

The following diagram shows the major components of the Android operating system. Each section is described in more detail below.

Applications

Android will ship with a set of core applications including an email client, SMS program, calendar, maps, browser, contacts, and others. All applications are written using the Java programming language.

Application Framework

By providing an open development platform, Android offers developers the ability to build extremely rich and innovative applications. Developers are free to take advantage of the device hardware, access location information, run background services, set alarms, add notifications to the status bar, and much, much more.

Developers have full access to the same framework APIs used by the core applications. The application architecture is designed to simplify the reuse of components; any application can publish its capabilities and any other application may then make use of those capabilities (subject to security constraints enforced by the framework). This same mechanism allows components to be replaced by the user.

Underlying all applications is a set of services and systems, including:

A rich and extensible set of Views that can be used to build an application, including lists, grids, text boxes, buttons, and even an embeddable web browser
Content Providers that enable applications to access data from other applications (such as Contacts), or to share their own data
A Resource Manager, providing access to non-code resources such as localized strings, graphics, and layout files
A Notification Manager that enables all applications to display custom alerts in the status bar
An Activity Manager that manages the lifecycle of applications and provides a common navigation backstack

For more details and a walkthrough of an application, see the Notepad Tutorial.

Libraries

Android includes a set of C/C++ libraries used by various components of the Android system. These capabilities are exposed to developers through the Android application framework. Some of the core libraries are listed below:

System C library - a BSD-derived implementation of the standard C system library (libc), tuned for embedded Linux-based devices
Media Libraries - based on PacketVideo's OpenCORE; the libraries support playback and recording of many popular audio and video formats, as well as static image files, including MPEG4, H.264, MP3, AAC, AMR, JPG, and PNG
Surface Manager - manages access to the display subsystem and seamlessly composites 2D and 3D graphic layers from multiple applications
LibWebCore - a modern web browser engine which powers both the Android browser and an embeddable web view
SGL - the underlying 2D graphics engine
3D libraries - an implementation based on OpenGL ES 1.0 APIs; the libraries use either hardware 3D acceleration (where available) or the included, highly optimized 3D software rasterizer
FreeType - bitmap and vector font rendering
SQLite - a powerful and lightweight relational database engine available to all applications

Android Runtime

Android includes a set of core libraries that provides most of the functionality available in the core libraries of the Java programming language.

Every Android application runs in its own process, with its own instance of the Dalvik virtual machine. Dalvik has been written so that a device can run multiple VMs efficiently. The Dalvik VM executes files in the Dalvik Executable (.dex) format which is optimized for minimal memory footprint. The VM is register-based, and runs classes compiled by a Java language compiler that have been transformed into the .dex format by the included "dx" tool.

The Dalvik VM relies on the Linux kernel for underlying functionality such as threading and low-level memory management.

Linux Kernel

Android relies on Linux version 2.6 for core system services such as security, memory management, process management, network stack, and driver model. The kernel also acts as an abstraction layer between the hardware and the rest of the software stack.

Is Android a Linux ?

noreply@blogger.com (Arun Tom) — Tue, 05 Jul 2011 05:11:00 +0000

Is Android a Linux Distribution?

Although the platform built on top of the Linux kernel, according to Google Engineer Patrick Brady, it is not a Linux distribution. It does not support the X-windowing system nor does it use the standard Linux libraries including the Gnu C Library. In fact, the C language is not even officially supported.

Even though Google denies that they are creating a Linux distribution, many people in the tech world refuse to believe it (see articles here and here). Instead they believe that Google is stealthily setting the stage to bring Linux into the mainstream and take on Microsoft.

What will Android do for Linux?

Whether or not Android is a Linux distribution, it will still bring attention to the Linux operating system. Very few people in the mainstream understand that there is a difference between the Linux kernel and a Linux distribution. Android will be a Linux “flavor” whether it wants to be or not.

When Android was only able to run on mobile phones, this was not too big of a deal. People are used to having different apps for the iPhone than there are for the Blackberry. Not being able to use an app designed for a LiMo based phone on an Android based phone is not an issue.

However, now that Android is being ported to Netbooks, the fact that it does not natively support applications designed for Linux may be a bit confusing at first. Fortunately, the operating system is completely open source. There are already suggestions for the creation of an Android application that allows for the use of a sandboxed Linux environment in order to run native Linux applications.

Conclusion

The fact that Google and the OHA used the Linux kernel for its operating system is mutually beneficial for both Linux and Android. Linux is a powerful and stable kernel on which to build an operating system. And, of course, being open source means millions of eyes on the code, creating a better product. However, the mainstream consumer probably won’t care about that. Instead, they will take notice because it is backed by Google. Linux may have finally gotten the push it needs to take on Microsoft.

Linux Mobile Phones

noreply@blogger.com (Arun Tom) — Tue, 05 Jul 2011 04:40:00 +0000

This LinuxDevices guide provides pointers to our coverage of Linux-based cellular mobile phones, feature phones, and smartphones. For desktop IP phones, please see the separate Linux IP Phones showcase.

ZiiLabs Zii Trinity -- This mid-range smartphone development platform from Creative Technology subsidiary ZiiLabs supports both Android and ZiiLabs' Linux-based "Plaszma" stack. The Zii Trinity is based on ZiiLabs' dual ARM9-core "ZMS-05" SoC, and provides 1080p video output, OpenGL graphics, HSDPA, WiFi, Bluetooth, GPS, and a 3.1-inch, 800 x 480 OLED touchscreen.

Emblaze Mobile First Else -- Emblaze Mobile's "First Else" phone incorporates an "Else Intuition" UI layer based on Access' ALP 3.0 stack and the LiMo (Linux Mobile) spec. The First Else offers unified messaging, geo-tagging, multimedia, an RSS live-updated "newspaper," and a thumb-oriented, fan-like touch interface called sPlay.

Samsung Galaxy Spica I5700 -- This scaled-down version of the Samsung I7500 "Galaxy" Android phone is equipped with an 800MHZ application processor and 180MB internal memory, and supports microSD cards up to 32GB. Measuring 4.5 by 2.2 by 0.5 inches, the Europe-destined, Android-ready Galaxy Spica I5700 offers a 3.2-inch touchscreen with 480 x 320 resolution, plus HSDPA, GPS, WiFi, Bluetooth, and a 3-megapixel camera.

Nokia N900 -- The N900 smartphone is Nokia's first phone to run Maemo Linux instead of Symbian. Running on a TI OMAP3430 system-on-chip with 1GB of memory and 32GB flash, the N900 offers a 3.5-inch, 800 ◊ 480 touchscreen, five-megapixel camera, slide-out QWERTY keyboard, plus WiFi, GPS, Bluetooth, and accelerometers.LG Eve GW620 -- LG's first Android phone, a QWERTY slider called the "Eve," is first available on Rogers Wireless' network in Canada. LG's Eve GW620 ships with up to 150MB RAM and 2GB flash, expandable to up to 16GB via a microSD slot, and offers a 3-inch, 480 x 320 resistive touchscreen and a five-megapixel camera.

HTC Droid Eris -- Sold by Verizon Wireless, HTC's Droid Eris is based closely on the HTC Hero, and likewise offers HTC's Sense UI running on top of Android. The Eris offers a 550MHz ARM Cortex-A8 based CPU, 288MB RAM, 512MB internal flash, an 8GB microSD card, a 3.2-inch 320 x 480 touchscreen, plus WiFi, Bluetooth, USB, GPS, digital compass, and a five-megapixel camera.

Vodafone 360 Samsung M1 -- ike the more advanced 360 H1, the M1 is a LiMo-compliant "360" smartphone built by Samsung and offered by Vodafone to its European customers. The Vodafone 360 Samsung M1 lacks WiFi, but offers a 3.2-inch touchscreen, HSDPA, 3G, Bluetooth, and a three-megapixel camera, and runs Vodafone's "360" social networking interface.

Sony Ericsson Xperia X10 -- Sony Ericsson's first Android phone offers its own "UX" user interface targeting social networking. The Xperia X10 provides from 8GB to 16GB of flash storage, a generous four-inch touchscreen, and an 8.1-megapixel camera with face recognition and geo-tagging, plus the usual 3G, WiFi, Bluetooth, and GPS features.

Droid by Motorola -- Verizon Wireless' first Android phone is built by Motorola and appears to be the early market leader among high-end Android phones. The slider-based "Droid" offers a 550MHz ARM Cortex-A8 processor, a 3.7-inch touchscreen, a five-megapixel camera, voice recognition, and Google Maps Navigation with turn-by-turn voice guidance. Huawei T-Mobile Pulse -- Offered by T-Mobile UK, Huawei's tri-band 3G T-Mobile Pulse is equipped with 2GB of SD memory and a 3.5-inch touchscreen. The mid-range Pulse offers WiFi, GPS, and a 3.2 megapixel camera, and provides a touted four and a half hours of talk time.

Dell Mini 3i -- Dell's first Android phone debuted in China, and is offered by China Mobile. The mid-range Dell Mini 3i device offers a 3.5-inch touchscreen, Bluetooth, and a three-megapixel camera. Acer Liquid -- Acer's first Android smartphone is also the first Android phone based on Qualcomm's 1GHz Snapdragon processor. The Acer Liquid offers a WVGA touchscreen, HSPA 3G support, WiFi, GPS, Bluetooth, and a five-megapixel camera. Samsung Moment -- Offered by Sprint, this Samsung-built Android handset is based on an 800MHz Samsung processor. Additional features offered by the Samsung Moment include a 3.2-inch AMOLED touchscreen, 3.2-megapixel camera, WiFi, Bluetooth, and GPS.

Samsung Behold II --This T-Mobile network Android phone offers a 3.2-inch AMOLED touchscreen with Samsung's TouchWiz UI running on top of Android. The Samsung Behold II provides WiFi, Bluetooth, GPS, and a five-megapixel camera.

Samsung Vodafone 360 H1 -- Vodafone's Samsung-built "360 H1" smartphone offers a 3.5-inch WVGA AMOLED display, and complies with the LiMo (Linux Mobile) Release 2 spec. The 2.3 x 4.6 x 0.5-inch Vodafone 360 H1 is equipped with a TI OMAP3430 system-on-chip, 16GB of flash, a 3.5-inch WVGA AMOLED touchscreen with multi-touch, HSDPA, WiFi, Bluetooth, GPS, FM radio, and sensors. Motorola Cliq -- Motorola's first Android smartphone, offered by T-Mobile, debuts a "push" social networking streaming web service and UI stack called MotoBlur. The slider-format Cliq smartphone offers a 3.1-inch HVGA touchscreen, a 5-megapixel autofocus camera, GPS, 3G HSDPA, WiFi, Bluetooth, and various sensors.

Palm Pixi -- Palm's second phone to run its Linux-based WebOS operating system is a scaled-down version of the Palm Pre, and is likewise available on Sprint. The Palm Pixi runs a new Qualcomm MSM7627 SoC, and offers a 2.8-inch, 320 x 400 touchscreen, an exposed QWERTY keyboard, and 3G support.

HTC Tattoo -- HTC's Android-based Tattoo is a scaled-down version of the HTC Hero, offering the same "Sense" UI stack. The HTC Tattoo provides a 2.8-inch touchscreen, HSPA, WCDMA, and quad-band GSM/GPRS/EDGE network support, plus WiFi, Bluetooth, GPS, and a 3.2-megapixel camera.

Miutech HDPC -- Miutech's HDPC (hybrid dual portable computer) squeezes an Atom-powered PC and an ARM-based mobile phone into a single package. Sporting dual displays, the Linux-ready HDPC offers a 5-megapixel camera, dual VGA video cameras, Ethernet, WiFi, cellular, GPS, and T-DMB terrestrial video.

Nuvifone G60 -- Developed by the Garmin-Asus partnership between manufacturer Asus and PND vendor Garmin, the Nuvifone G60 is billed as an all-in-one phone, web browsing device, and personal navigator. The Nuvifone G60 ships with 128MB RAM and 4GB flash, offers quad-band GSM and HSDPA cellular support, as well as 802.11b/g WiFi, and Bluetooth. HTC T-Mobile MyTouch 3G --Offered by T-Mobile, the HTC-made, Android-based MyTouch 3G provides customization options both in the UI and via various skins and accessories. The MyTouch 3G eliminates the HTC G1's slide-out keyboard, and offers a 3.2-inch, 320 x 480 screen with a QWERTY touchscreen display, as well as a 3.2-megapixel camera.

Vobis Highscreen PP5420 -- Vobis Computers' "first Russian-market Android phone" appears to be an Android-converted version of the company's Windows Mobile-based Mobinnova ICE smartphone. The Highscreen PP5420 includes a 528MHz Qualcomm processor, HSDPA support, and a secondary OLED touchscreen in addition to its main 3-inch WQVGA display.

HTC Hero -- The HTC Hero is notable in that it debuts the company's new UI layer called HTC Sense. Physically, the Hero is fairly similar to other early HTC Android phones, equipped with the ARM-based Qualcomm MSM7200a system-on-chip, and offering a 3.2-inch, QVGA touchscreen, HSDPA, WiFi, Bluetooth, GPS, accelerometer, and digital compass. Palm Pre -- The Palm Pre smartphone features Palm's homegrown, Linux-based WebOS operating system, which is touted for its customization, multi-tasking, syncing, and social networking features. The Palm Pre provides WiFi, GPS, a three-megapixel camera, a 3.1-inch touchscreen, and a rounded design with a keyboard that slides out on a curved slider. GizmoForYou Flow --This Linux hardware/software kit for building a modular touchcreen smartphone is available from open source hacker community GizmoForYou. Based on the TI OMAP35x-based Gumstix Overo Earth single-board computer, the Flow phone offers modules including GPS, 3.5G cellular, Bluetooth, WiFi, and a camera.
ROAD Handy-PC Officer S101 -- This upgraded version of the Handy-PC PDA from Germany-based ROAD is now a multifunction, Linux-based mobile phone. Based on a 512MHz Marvell PXA270, the Handy-PC Officer S101 can act as both a GSM cellular phone and a WiFi-driven PDA and web browser, and it offers a dual SIM-card option.

Samsung I7500 -- Samsung's first Android phone was introduced by Telefonica's O2 network in Germany. The Samsung I7500 offers a 3.2-inch AMOLED touchscreen, 7.2Mbps HSDPA, WiFi, Bluetooth, GPS, and a five-megapixel camera.

Motorola Evoke QA4 -- otorola's EV-DO smartphone offers both a slide-out keypad and a virtual QWERTY keyboard. The Evoke QA4 runs Motorola's MotoMAGX Linux/Java stack, and is equipped with a 2.8-inch touchscreen, accelerometers, and widgets, as well as OK Labs' OKL4 embedded hypervisor.

Motorola A1210 -- The Motorola A1210 appears to be an updated version of the popular Motorola Ming, and is likewise aimed at the Chinese market. The GSM/EDGE-ready A1210 offers a larger 2.8-inch screen, and an improved 3.1 megapixel camera.

Yuhua Xphone-SDK -- Feb. 24, 2009 -- This hardware reference smartphone design from Chinese mobile ODM (original design maker) Yuhua runs the Linux-based Android mobile stack. The Xphone-SDK runs Android on a 624MHz PXA-310 SoC, with 128MB SDRAM and 256MB of flash, and offers a 3-inch screen, tri-band GPRS/EDGE capability, 3-megapixel camera, Bluetooth, and WiFi.

General Mobile DSTL1 -- Feb. 23, 2009 -- General Mobile's dual-SIM, XScale-based Android cameraphone is based on a design by Yuhua (see entry above). The DSTL1 runs Android on a Marvell PXA-310 clocked to 624MHz, offers WiFi, Bluetooth, accelerometers, and a 5-megapixel camera, and is equipped with dual SIMs and dual baseband radios, enabling simultaneous reception for two different phone numbers.

NEC DoCoMo N-01A, N-02A, N-03A, and N-04A -- Feb. 18, 2009 -- These four new LiMo-compliant 3G handsets from NEC are available for NTT DoCoMo's HDSPA FOMA network in Japan, supporting up to 7.2Mbps downlinks. The new phones include the DoCoMo Prime series N-01A (pictured), which offers gesture recognition technology, as well as the DoCoMo Style series N-02A (5.2-megapixel camera), DoCoMo Style series N-03A (fashion colors), and business-oriented DoCoMo Smart series N-04A.

Panasonic DoCoMo P-01A, P-02A, P-03A, P-04A, and P-05A -- Feb. 18, 2009 -- These four new LiMo-compliant 3G handsets from Panasonic are available for NTT DoCoMo's HDSPA FOMA network in Japan, supporting up to 7.2Mbps downlinks. The phones include the double-open format DoCoMo Prime series P-01A (pictured), the DoCoMo Style series P-02A (480 x 854 resolution display), DoCoMo Style series P-03A (OLED sub-display), DoCoMo Smart series P-04A (slim and light), and the no-nonsense DoCoMo Smart series P-05A.

Google Android Dev Phone 1 -- The Android Dev Phone 1 is a version of the HTC G1 offered by Google with the SIM- and other hardware unlocked. The Android Dev Phone 1 aims to provide Android developers with real hardware on which to test their applications, and is sold for $400 (or $425 with network member fee).

Kogan Agora -- Dec. 04, 2008 -- The "first Aussie phone powered by Android," as Kogan Technologies calls it, is sold without a contract to a global market. Both the standard and "Pro" versions of the Kogan Agora run the Linux-based Android phone spec and offer 3G and Bluetooth connectivity, while the "Pro" adds a 2-Mpixel camera, WiFi, and GPS.

Motorola MotoRokr EM35 -- Dec. 02, 2008 -- Motorola's MotoRokr EM35 is a slider version of the EM30 music phone, and runs MontaVista Linux. The EM35 offers Bluetooth, USB, a 3-megapixel camera, and a haptic scroll interface, as well as music playback that is said to include virtual surround effects.

Qigi i6-Goal -- Dec. 01, 2008 -- Offered by Qigi Future Technology and TechFaith Wireless for the China market, the i6-Goal is only the second Android phone to be announced. The phone is said to include a 2.8-inch touchscreen, quad-band GSM/GPRS/EDGE, WiFi, GPS, Bluetooth, and a 2-megapixel camera.

Koolu W.E. Phone for Android -- Nov. 20, 2008 -- Koolu, which offers its own "W.E. Phone" version of the Linux-ready Openmoko Neo FreeRunner, is now offering an Android version of the W.E. Phone/FreeRunner. Like the FreeRunner, the unofficially named W.E. Phone for Android incorporates a 400MHz Samsung S3C2442 (ARM9 core), 128MB of RAM, 256MB of flash, a 2.8-inch 640 x 480 TFT display, tri-band GPRS/GSM cellular, WiFi, Bluetooth, GPS, and accelerometers.

Moto VE66 -- Nov. 18, 2008 -- Motorola's Moto VE66 cameraphone offers WiFi, GPS, a 5-megapixel camera, an MP3 player, and MontaVista Linux. The VE66 is the first Motorola phone to support the MotoDev Studio for WebUI "widget" platform.

Motorola Krave ZN4 -- Oct. 21, 2008 -- Motorola's first Linux-based touchscreen phone for the U.S. market is being distributed by Verizon. The Krave ZN4 appears to be an Americanized version of Motorola's Asia-targeted MotoMing A1600, which offers GPS, handwriting recognition, business card scanning with OCR, and a 3.2-megapixel camera.

Emblaze Mobile Edelweiss -- Oct. 10, 2008 -- Israel-based Emblaze Mobile is selling this large-screen smartphone to the Russian market. Based on a Texas Instruments OMAP3x processor, the "Edelweiss" phone offers an unprecedented 3.5-inch, 854 x 480 touchscreen, plus GPS, WiFi, Bluetooth, HDSPA, micro-USB, and a 3.2MP camera, and runs the Access Linux Platform (ALP) stack.

HTC G1 -- Sep. 23, 2008 -- The first "Android" phone is manufactured by HTC, sold by T-Mobile, and runs Android software from Google. Selling for only $180, the G1 offers 1GB of flash, a 3.2-inch touchscreen haptic display, a slide-out keyboard, plus WiFi, Bluetooth, and GPS.

Panasonic FOMA P706ie -- Sep. 22, 2008 -- This LiMo-compliant phone from Panasonic Mobile Communications targets NTT DoCoMo's FOMA network. The FOMA P706ie offers a 3-inch QVGA display, a 2-megapixel camera, a 2GB or 8GB memory card, voice clarification, and video record and playback at up to 15fps.

CRC Openmokast -- Sep. 10, 2008 -- The "Openmokast" phone prototype from Communications Research Center Canada (CRC) is a physically augmented version of OpenMoko's open-source Neo FreeRunner phone, and is designed for receiving datacasting signals. Along with typical OpenMoko smartphone functions, the Openmokast supports reception of live digital radio, video, and data broadcasts.

Samsung Anycall SCH-i859 "Olympics" -- Sep. 03, 2008 -- This Samsung Electronics "Anycall" phone is being distributed by China Unicom, and runs the Mizi Prizm mobile Linux stack. Samsung's "Olympics" phone, also called the SCH-i859, is equipped with a Marvell PXA300 processor, a 2.8-inch, 320 x 240-resolution touchscreen, 128MB ROM, 64MB SDRAM, a 3-megapixel camera, USB, Bluetooth, and a MicroSD slot.

Motorola Rokr EM30 -- Aug. 05, 2008 -- Motorola's LiMo-compliant Rokr EM30 is aimed at "mass-market" music lovers. A lower-cost version of the the Rokr E8 design, the GSM quad-band phone offers the same "ModeShift" technology, which changes with the phone's mode and enables single-click shifts between modes, but has replaced the E8's haptic scroll interface with a traditional four-sided wheel.

Koolu W.E. Phone -- Jul. 21, 2008 -- A version of OpenMoko's Linux-based Neo FreeRunner distributed by Kooku in the Americas, the U.K., and the European Union, the W.E. Phone adds Google Apps to FreeRunner's software mix.

Motorola MotoMING A1600 -- Jul. 08, 2008 -- Motorola's Linux-based Ming A1600 offers GPS, handwriting recognition, business card scanning with OCR, and a 3.2-megapixel camera. It replaces the classic A1200, which may have been the best-selling Linux-based smartphone to date.

OpenMoko NeoFreerunner -- Jul. 02, 2008 -- Billed as a completely open source, hackable hardware platform, the Neo FreeRunner is the first OpenMoko phone intended for widespread use by non-developers. Frequent software upgrades are planned. Motorola MotoZine ZN5 -- Jun. 23, 2008 -- A cameraphone that combines Motorola's "ModeShift" interface with Kodak imaging technology, Motorola's MotoZine ZN5 mashes up a 5-megapixel camera with a multimedia smartphone. It uses Motorola's ModeShift soft MMI (man-machine interface), which changes the faceplate's format and function for separate telephony, photo-videography, and media playback modes.

Tranzda Technologies NewPlus TGP-369, TFX-326, TGP-802, TFX-320, and T818 -- Jun. 02, 2008 -- Shenzhen, China-based smartphone design company Tranzda Technologies has five phone designs that use its NewPlus Linux phone application stack. All five include GPS, along with optional features that include WiFi, cameras, and biometric fingerprint authentication.

Motorola MobileTV DH02 -- Mar. 31, 2008 -- Further blurring the lines between cellphones and portable media players (PMPs), Motorola's MobileTV DH02 adds a 3G (HDSPA/GPRS) mobile phone, GPS, and a larger 4.8-inch, 480x272 display to its DH01 PMP. Like the DH01, the touchscreen-enabled DH02 can receive and record video broadcasts in DVB-H format (digital video broadcast, handhelds), and offers gesture-based UI, Bluetooth, and voice-assisted navigation software.

Motorola U9 -- Feb. 11, 2008 -- Announced as part of the first wave of 18 LiMo-compliant models, the Motorola U9 boasts a rounded, contemporary flip-phone form factor. The U9 supports Quad-Band GPRS Class 12/EDGE Class 12 service, and is equipped with Bluetooth, a USB port, and both a 2-inch QVGA internal TFT display and an OLED-based 1.45-inch external display.

Mizi Prizm/Mobile -- Feb. 04, 2008 -- This mobile-phone reference design from Korea-based Mizi Research is based on its Linux-compatible "Prizm" phone stack. Designed for low-cost phones, the Mizi Prizm/Mobile design supports CDMA, GSM, GPRS, and Edge cellular protocols, with plans for adding TV and GPS support.

Purple Labs Purple Magic -- Jan. 31, 2008 -- This LiMo-compliant reference design from French mobile Linux phone stack firm Purple Labs is based on NXP Semiconductors's Nexperia 7210 system-on-chip (SoC) reference design. The sub-$100 Purple Magic offers 3G cellular service and runs Linux and a telecom RTOS on a single ARM9 core, thanks to embedded virtualization technology from VirtualLogix.

Motorola Rokr E8 -- Jan. 10, 2008 -- The Rokr E8 is Motorola's first phone with a soft MMI (man-machine interface) that changes with the phone's mode. The quad-band GSM/GPRS phone has a 2-megapixel camera, multi-codec music player, a "full" HTML browser, and unique "haptics" system aimed at providing "tactile response" to virtual keypresses.

Wistron NeWeb PDA and Dual Net Phone-GW4 -- Jan. 8, 2008 -- Wistron NeWeb Corp. (WNC) is showing a hybrid GSM/VoWiFi phone that runs Linux. The PDA and Dual Net Phone-GW4 boasts a 2.5-inch touchscreen and a full QWERTY keyboard.

OpenMoko Neo FreeRunner -- Jan. 3, 2008 -- Open source phone company OpenMoko will ship a new version of its user-modifiable Linux-based mobile phone next year. The "Neo FreeRunner" resembles OpenMoko's original Neo1973 model, but with WiFi, 3D accelerometers, and a faster processor, as well as a consumer market focus, according to the company.

Motorola RAZR2 V8 -- Aug. 7, 2007 -- Motorola started shipping its first Linux-based mobile phone "bound for North America," it said. The RAZR2 V8 is a highly multimedia-oriented phone, with features such as the Windows Media Player 11 codec, a USB 2.0 interface supporting "high speed" (480Mbps) file transfers, and a "music touchscreen" on the external display.

OpenMoko Neo1973 -- Jul. 9, 2007 -- A project to build an open, user-extensible Linux-based mobile phone has opened its online store for business. About 1,000 OpenMoko Neo1973 phones are available initially, primarily targeting hackers and developers. Like Apple's iPhone, the Neo1973 eschews hardware buttons in favor of a touchscreen. Its 2.8-inch TFT touchscreen has a resolution of 640 x 480 (VGA)double that of the iPhone's.

Tranzda PM328 -- Mar. 15, 2007 -- A Linux-based phone with mapping and voice navigation capabilities has gone on sale in China. The Tranzda PM328 can help users locate nearby businesses, such as restaurants and gas stations, and then guide them to their destination with voice prompts. The Tranzda PM328 has a thin form-factor just 0.6 inches (16mm) thick, and includes a USB port and a Bluetooth radio.

Accton VM3228T -- Mar. 7, 2007 -- Taiwan-based phone designer and manufacturer Accton Technology Corp. is marketing a Linux- and Qtopia-based dual-mode phone design said to support both quad-band GSM and 802.11b/g networks. The VM3228T offers rich multimedia capabilities, and features seamless cellular/WiFi switch-over based on 3GPP standards, says Accton.

Grundig B700 -- Mar. 2, 2007 -- Less than two weeks after launching its Linux-based "single core" U900 phone aimed at the mid-range market, Grundig Mobile has introduced another Linux-powered smartphone. The B700 targets enterprise users with a full hardware QWERTY keyboard and push email, similar to RIM's Blackberry.

Gupp Phreedom -- Feb. 26, 2007 -- A startup in Penang, Malaysia is readying a Linux-based dual-mode WiFi GSM/GPRS phone expected to ship in Q2. Gupp Technologies's "Phreedom" phone boasts a Treo-style QWERTY keyboard, a 2.5-inch QVGA color screen, and VoWiFi (voice-over-WiFi) capabilities based on the SIP standard.

Grundig U900 -- Feb. 23, 2007 -- Grundig Mobile has launched a Linux phone based on a single-core, single-chip architecture, long considered to be the "holy grail" of modern handset technology. The U900 runs Linux and an RTOS (real-time operating system) on an NXP ARM9-based SoC (system-on-chip), using VirtualLogix platform virtualization technology.

Infineon MP-Elite -- Feb. 14, 2007 -- Infineon, Comneon, and FSMLabs demonstrated a working prototype of a single-core mobile phone, making real calls on an Edge network, at the 3GSM World Congress this week in Barcelona. The partners claim their MP-Elite phone to be the first at its price point to run Linux. .

Motorola MotoRIZR Z6 -- Feb. 12, 2007 -- Motorola is showcasing its Linux and "kJava" based music phone for U.S. and European markets, at the 3GSM World Congress this week in Barcelona. The MotoRIZR Z6 is said to be based on a "new Linux operating system that incorporates kJava."

Motorola Rokr E6 (aka E690) -- Dec. 1, 2006 -- Taiwanese pop superstar Jay Chou launched Motorola's thin, Linux-powered Rokr E6 multimedia phone, at the ITU Telecom World tradeshow in Hong Kong. The fourth-generation music phone is just over half an inch thick (14mm), and features a 2-megapixel camera and business card reader.

FIC Neo1973 -- Nov. 1, 2006 -- The first phone based on the open source OpenMoko platform, the Neo1973 is an unlocked GSM/GPRS phone with built-in GPS receiver, ultra-high resolution display, and user-modifiable Linux-based firmware.

E-Ten G500 -- Nov. 1, 2006 -- Linux is running on E-Ten's G500, a PDA/phone with integrated GPS that ships with Windows Mobile. Along with the kernel, the EtenG500 Linux project has HaRET (handset reverse-engineering tool) and the GPE palmtop environment working, opening the door for volunteers to enhance the device's Linux stack.

Samsung/ Eidicom Qtopia Phone design -- Oct. 1, 2006 -- Samsung and Eidicom have created what appears to be a Linux-based dual-mode camera-phone reference design incorporating Trolltech's Qtopia Phone Edition (QPE) UI and application platform. Photos of the device and its development kit were published by Korean news outlet AVING.net.

D-Link V-Click -- Oct. 1, 2006 -- An unlocked, dual-mode WiFi and GSM/GPRS phone, the "V-Click" appears to be a rebranded Linux- and Qtopia-based design created by Taiwanese ODM (original design manufacturer) Wistron NeWeb Corp. (WNC). It will ship in Q1, 2007.

NEC N902iX -- Aug. 24, 2006 -- The N902iX phone works with DoCoMo's 3.5G HSDPA network, and is capable of peak download speeds of 3.6Mbit/sec. It has a bevy of music, security, camera, and other features that U.S. and European users can only dream of.

Trolltech Qtopia Green Phone -- Aug. 18, 2006 -- The "Greenphone" features a user-modifiable Linux OS, and is meant to jumpstart a third-party native application ecosystem for Linux-based mobile phones around Trolltech's Qtopia development framework and graphics stack. The phone is made by Yahua TelTech.

Samsung SGH-i858 -- Aug. 1, 2006 -- A new Linux-based phone for subscribers of China Mobile's "Go-Tone" GSM/GPRS service, the Samsung SGH-i858 features a large, 2.4-inch QVGA (240 x 320) color touchscreen, along with a slide-out hardware keypad. It runs version 2.5 of Mizi's "Prizm" Linux phone stack.

Motorola SCPL -- Jul. 27, 2006 -- The Scpl ("scalpel") is the successor to Motorola's ubiquitous Razr phone, and is due in Oct. 2006. Starting with the Sclp, Motorola will abandon the proprietary "P2K" OS used in the Razr and other currently or soon-to-be shipping models, such as the Rizr, Krazr, and RazrMaxx, in favor of a Linux-based OS, it says.

Motorola Rokr -- Jul. 14, 2006 -- Motorola's third-generation music phone, the Rokr E2 uses Motorola's new keypad-driven "chameleon" OS. It has lots of other neat features, too.

Neuf Twin -- Jun. 20, 2006 -- The first dual-mode WiFi/cellular phone available in France, Neuf's Linux-based "Twin" phone draws praise for its small size, PDA-like features, and responsive, simple user interface.

Panasonic P902iS -- Jun. 5, 2006 -- Panasonic is shipping another Linux-based mobile phone to NTT DoCoMo, for use with DoCoMo's FOMA ("Freedom of Mobile Multimedia Access") 3G network. The P902iS is compatible with DoCoMo's Chaku-Uta music download service, and supports 2GB miniSD cards for storage of up to 1000 songs.

Grundig G500i -- May. 15, 2006 -- The Grundig G500i Dreamphone is the first Linux-based iMode phone available in Europe, and the first of several planned Linux-based models from Purple Labs. Purple Labs developed the phone over the course of two years, and it is available in France today for as little as $13, with a calling plan. Read all about the process, in our exclusive interview with COO Jean-Marie Andre.

Samsung SCH-i819 -- May. 8, 2006 -- Samsung has shipped a new Linux-based smartphone in China. The SCH-i819 targets Chinese business travelers, and is the first Linux phone to support dual-band cellular operation with both CDMA 1x (800MHz) and dual-band GSM (900/1800MHz) networks, according to Mizi Research, which supplied the phone's Linux stack.

ImCoSys dual-mode GPS smartphone -- Feb. 23, 2006 -- A dual-mode Linux smartphone that also integrates a GPS (global positioning system) receiver, WiFi, and Bluetooth, the ImCoSys smartphone is a quad-band GSM design with a PDA-like form-factor.

Haier N60 -- Feb. 22, 2006 -- A tri-band GSM/GPRS Linux cameraphone that supports WiFi and Bluetooth through an SDIO interface. Has a QVGA (240 x 320) color touchscreen, a 1.3 megapixel camera, and an integrated MP3 player.

Panasonic P901iTV -- Feb. 21, 2006 -- A Linux-based mobile handset capable of receiving digital or analog television, the "P901iTV" features a pivoting 2.5-inch color LCD. It works with NTT DoCoMo's 3G network in Japan, where digital TV services will launch this spring, DoCoMo says.

G-Tek PWG500 -- Feb. 16, 2006 -- A very basic, simple, dual-mode WiFi/quad-band GSM/GPRS phone that can provide Internet access to PCs and PDAs connected via USB or Bluetooth, the PWG500 can also provide "seamless roaming" between WiFi and mobile networks, when used with LongBoard's FMC software.

E28 FMC phones -- Feb. 14, 2006 -- Linux smartphone pioneer E28 Limited has partnered with fixed-mobile convergence (FMC) infrastucture equipment pioneer Bridgeport Networks to demonstrate 3G/WiFi live-call handoff, at 3GSM this week in Barcelona. The joint technology uses Linux extensively, and offers operators a standards-based dual-mode package based on devices with feature-phone pricing.

Accton VM1188T -- Feb. 13, 2006 -- A peer-to-peer WiFi VoIP phone from Taiwanese ODM Accton, the VM1188T phone will enable "anyone with an Internet connection" to place "free, high-quality phone calls," Accton claims, without booting up a computer.

Samsung SGH-i858 -- Jan. 15, 2006 -- A Linux-based mobile phone with a "slider" style case, the SGH-i858 is a GSM phone that has been submitted to the FCC for possible sales in the US. It features a QVGA (320x240) color touchscreen, bluetooth, IrDA, TV out, and microSD storage.

Wistron NeWeb GW1 -- Jan. 5, 2006 -- A dual-mode cellular/VoIP phone that appears to be based on Linux and a branded version of Trolltech's Qtopia Phone Edition (QPE), The GW1 from Taiwanese ODM Wistron NeWeb Corp. (WNC) was reportedly demonstrated the 2006 Consumer Electronics Show (CES) in Las Vegas.

HTC Blue Angel / Xanadux -- Jan. 3, 2006 -- A Windows CE PDA phone that is making and receiving phone calls under Linux, thanks to work done by the Xanadux project.

NEC N902i -- Oct. 28, 2005 -- A four-megapixel camera phone based on a CCD (charge-coupled device), with an image stabilization feature claimed to reduce blurriness in low-light settings, the N902i has a 2.5-inch "QVGA+" (325 x 240) LCD main display supporting 262K colors, as well as a 1-inch, 120 x 90 sub display supporting 65K colors. The phone has a MiniSD card slot, for storing photos and other user files.

Panasonic P902i -- Oct. 28, 2005 -- Panasonic's P902i aims to appeal to music lovers, with music jukebox software and support for BlueTooth headphones. An available 1GB MiniSD card can store about 250 songs, the company says. Users can change sound quality settings on the fly, and purchase music from online providers.

Cellon Int'l C8000/Philips CT9688 -- Oct. 20, 2005 -- Cellon claims to be the "world's largest independent design house for wireless devices." It used embedded Linux to build its top-of-the-line smartphone platform, the, C8000, which has already shipped in Europe under a major brandnameprobably the Philips CT9688, pictured at left.

TCL e787 -- Sep. 6, 2005 -- A high-end dual-band GSM/GPRS smartphone that features a 2MP camera, Bluetooth, multimedia players, an Internet phonebook feature, PC synchronization, and a document viewer from Picsel Technologies.

Longcheer/Oswin Linux PDA phone -- Aug. 18, 2005 -- A PDA phone to be jointly developed by a Chinese mobile phone hardware vendor and a Singaporean smartphone and PDA phone designer.

Motorola A728 -- Jul. 27, 2005 -- A cost-optimized version of Motorola's earlier A760i and A768i (which in turn are tri-band versions of the dual-band A760 and A768, respectively). Like those devices, the A728 is a tri-band 900/1800/1900 GSM phone certified as conforming to the European Union's Radio and Tecommunications Terminal Equipment (R&TTE) Directive. Unlike the A760i and A768i, however, it lacks Bluetooth, and has only a WAP2 browser. It has been available in China since Q2, 2005, Motorola says.

Motorola A732 -- Jul. 27, 2005 -- A tri-band GSM/GPRS phone with several features aimed at heavy text message users, including a slide-out keypad that doubles as a finger-driven input pad that recognizes Chinese or Roman characters. The A732 is expected to ship in Q3, 2005.

Motorola A910 -- Jul. 27, 2005 -- A new high-end Motorola Linux phone, the A910 includes built-in WiFi, along with UMA (Unlicensed Mobile Access) features aimed at providing seamless access to GSM and GPRS features over WLAN, on supported carrier networks.

ZTE e3 -- Jun. 27, 2005 -- A dual-band GSM phone with a unique pivoting touchscreen, from one of China's largest telecom equipment makers. ZTE's e3 has strong multimedia and video capabilities, along with handwriting recognition and Chinese-English translation software. It includes a 1.3 megapixel camera, supports numerous multimedia formats, stores up to 10 hours of MP3s, and boasts an Opera web browser with small-screen rendering technology.

Motorola E895 -- Jun. 27, 2005 -- A tri-band GSM Linux/Java phone targeting Asian markets, the E895 has a 1.3 megapixel camera, large TFT/LCD display, Bluetooth, and rich Internet, multimedia, and web capabilities, Motorola says.

Motorola E680i -- Apr. 11, 2005 -- A Linux-based MP3 player and cameraphone that support stereo bluetooth audio connectivity, an improved interface with full HTML browser, and user-upgradable storage.

Yulong Coolpad 858 -- Apr. 8, 2005 -- A GSM/CDMA phone from an ODM in Shenzhen, the Coolpad is based on Qtopia Phone Edition and runs a Linux-derived OS called LinuOS.

Siemens Concept Device -- Mar. 21, 2005 -- A digital video broadcast receiver that downloads programming over a cellular network, the Siemens conceptused to make calls.

Samsung Qtopia -- Mar. 20, 2005 -- A Linux-based phone, that's apparently based on the same hardware as the older SCH-i519, but which runs Qtopia Phone Edition, an off-the-shelf Linux application environment for mobile phones that shipped in May, 2004. The Samsung phone also supports UWB (ultra wideband) networking. .

ROAD Handy-PC -- Feb. 18, 2005 -- Flipping the Model S101 "Handy-PC" open reveals a keyboard and screen for interacting with computer applications. Flip it closed again, and it's a GSM phone. The device is based on a 400 MHz Intel XScale PXA263 processor running a Linux 2.6 kernel along with Trolltech's Qtopia graphical user interface and PIM suite. It comes with 64 MB of RAM and 64 MB of flash memory, measures 128 x 60 x 25 mm, and weighs in at 210 grams.

Motorola A1200 -- Jan. 9, 2005 -- A slim, lightweight flip-phone design similar to Motorola Razr phones, the A1200 was debuted by fashion designer Vivienne Tam at a Dec. 26 Shanghai press event. It has been registered with the FCC, suggesting it may soon reach the US.

Motorola Rokr E2 music phone -- Jan. 3, 2005 -- Motorola's second-generation music phone for US customers is based on Linux, and features USB 2.0, a normal (non-iTunes) mp3 player, built-in FM radio, and SD card storage.

NEC N900iL -- Nov. 19, 2004 -- NTT DoCoMo and its regional subsidiaries are offering business subscribers a dual-network 3G/VoIP handset that works as a 3G mobile phone, VoIP (voice-over-IP) terminal, or both simultaneously. The N900iL is based on a Linux-based 3G mobile phone software platform developed jointly by NEC and Panasonic.

Datang 3G Linux phone reference design -- Nov. 11, 2004 -- China's government-owned TEM (telecommunications equipment manufacturer) has developed a 3G Linux mobile phone reference design, expected to appear in products in mid-2005. Datang's Linux phone design works with networks based on TD-SCDMA, a 3G technology largely invented by Datang, which may see use outside China.

Yahua TelTech "Normandy" -- Sep. 27, 2004 -- A Chinese ODM (original design manufacturer) will ship a mobile phone based on Linux and Qtopia in Q1 of 2005. Yuhua TelTech's "Normandy" phone will use Qtopia Phone Edition (QPE), an application stack for mobile phones that includes a PIMS and other PDA-like features.

E28 E2800+ -- Aug. 10, 2004 -- Shanghai-based E28's e2800+ has been available in China since July, and builds upon E28's previous e2800 model, which was the world's first commercially available Linux smart phone, E28 says. The device, which targets business users, currently features dual-band 900/1800MHz communications, a GPRS/CSD modem, and a 300K pixel camera. A model that supports US communications standards at 900/1800/1900MHz is set to be launched shortly.

Motorola A780 -- Jul. 29, 2004 -- US mobile phone customers will at last gain the option of a Linux-based handset later this year, when operators begin offering a high-end Motorola Linux/Java smart phone aimed at business professionals. The A780 will roll out globally in early Q4, reaching select US regions before 2005, according to Motorola.

Wildseed mobile phone -- May. 12, 2004 -- This Linux-based wireless phone combines communications and entertainment in a uniquely customizable two-part design. The company plans to initially aim the device at the U.S. "teen market", by offering a colorful phone with "cool teen-oriented capabilities". It's built around an XScale microprocessor running Linux kernel 2.4.x. Clip-on "SmartSkins" provide customized look and feel, games, MP3 player, and more. Launch: July, 2004.

Motorola E680 -- Mar. 9, 2004 -- The E680, expected in late 2004, will include built-in stereo speakers and will download music and other multimedia files over USB, Bluetooth, or a cellular phone link one third the speed of a typical home DSL connection. MPEG4-enabled camera with 8x zoom, Java, and many PDA-like features.

Motorola A768 -- Feb. 19, 2004 -- A Linux-powered smart phone targeting enterprise customers now shipping in China. The A768 is essentially a revision of Motorola's first Linux-based smart phone, the A760, with new VPN, video, and other capabilities.

Samsung SCH-i519 -- Dec. 16, 2003 -- Samsung has begun shipping a new Linux-powered smartphone in China. The Samsung SCH-i519 smartphone supports both Chinese and English, and works with the CDMA2000 1x network of China's #2 wireless provider, Unicom. The device features voice control, a powerful 400MHz XScale PXA255 processor, and a Linux OS and software suite from Mizi Research. Our Device Profile features extensive details and many screenshots.

E28 E2800 -- Dec. 14, 2003 -- A Chinese company based in Shanghai named "E28" has quietly been selling Linux-based smartphones in China since August, and today launched its Linux device in Hong Kong. The company also claims to be in talks with US and European companies to bring the device to those regions, according to one source. E28's E2800 smart phone sells for about $600, and targets business users, offering PDA functions, touch-screen, handwriting recognition, a camera, and memory expansion to 512MB through an SD memory card.

Motorola A760 Linux/Java handset/PDA -- Feb. 14, 2003 -- This initial Motorola Linux/Java handset offering combines the functions of a mobile phone, PDA, digital camera, video player, MP3 player, speakerphone, messaging, Internet access, and Bluetooth wireless technology. Motorola will initially launch the A760 handset in Asia in 2003.

Telepong mobile phone -- Nov. 15, 2001 -- Currently under development, this device is aimed at the Euro "tweens market". It runs on a Linux-based operating system and has a built-in GPRS module, a 65K color display, and provides a WAP 1.2.1. compliant browser. It is EMS enabled and comes with a camera interface and a joy stick for embedded games.

Ericsson cordless webpad/phone -- Nov. 6, 2000 -- This device (formerly called the HS210 Cordless Screen Phone), is basically a wireless webpad with a built-in telephone and Bluetooth wireless technology for in-home use. It can surf the web, check email, send voice clips, and make phone calls.

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10+ mistakes Linux newbies make

noreply@blogger.com (Arun Tom) — Tue, 05 Jul 2011 04:19:00 +0000

New desktop users can make plenty of mistakes (as can anyone). But knowing which mistakes to avoid, from the start, helps prevent a LOT of frustration. I’ve handled the topic ofmistakes new Linux admins make, but never those of desktop users. Here are some of the most common Linux desktop mistakes I see new users make.

1: Assuming they are using Windows

Although this might seem way too obvious, it’s not. The average user has no idea there are even different operating systems to be had. In fact, most average users couldn’t discern Windows XP from Vista from 7 (unless they are certain Windows 7 was “their idea”). Because of this, new users might believe that everything works (or doesn’t work, as the case may be) as it does in Windows. Make your end users aware that they are using a different operating system — and that it works differently.

2: Trying to make exe files work

Unless you have done your homework and installed WINE, double-clicking those .exe files simply won’t do anything. And when that happens, your end users are going to be upset. I have seen many an end user download an app made for Windows assuming that it will work for Linux. Make it clear to users that Linux, like Windows, will only run applications made for that operating system. This, of course, is tossed out the window when WINE is involved. But new users won’t be using WINE anyway.

3: Choosing the wrong distribution

One of the biggest problems for users is choosing the wrong distribution. Imagine being a new user and selecting Gentoo or Slackware or Fedora! Yes those are all good distributions, but any of them would send a new user running away in fear. If you are in the initial stages of helping a new user out, do yourselves both a favor and choose the distribution carefully. Consider the user’s ability, needs, and hardware before you make that selection. Don’t just jump on board Ubuntu because everyone says you should. A lot of distributions out there are made specifically for new users. Give them all a close examination before making the choice.

4: Not finding software

Because so many new Linux users are migrating from Windows, they think software can be had from the same channels. Most of the time, this is not the case. The new user needs to become familiar with their package management tools right away - especially tools like Synaptic, Packagekit, and Ubuntu Software Center. Each of those tools is a mecca of software where users can most likely find all the applications they need.

5: Sending OpenOffice documents to Microsoft Office users in the default format

I see this so often. New Linux users are proud of the strides they have made but dumbfounded (and sometimes turned back to Windows) because the people they share files with can’t read their formats. Remember, Microsoft products are not good at getting along with other operating systems and other applications. Make sure your new users are saving in file formats that are readable by the Microsoft equivalents.

6: Avoiding the command line

I can’t, for the life of me, figure out why people completely avoid the command line as if it is the most complex tool there is. I know people who can work absolute magic with Photoshop but can’t seem to type a simple rm command at the command line. Why this is I will never know. New users shouldn’t shy away from the command line. Knowing the command line isn’t essential anymore, but it will make them more capable users.

7: Giving up too quickly

Here’s another issue I see all too often. After a few hours (or a couple of days) working with Linux, new users will give up for one reason or another. I understand giving up when they realize something simply doesn’t work (such as when they MUST use a proprietary application or file format). But seeing Linux not work under average demands is rare these days. If you see new Linux users getting frustrated, try to give them a little extra guidance. Sometimes getting over that initial hump is the biggest challenge they will face.

8: Thinking the Windows directory hierarchy translates to Linux

There is no C:\ in Linux. Nor do you use the “\” character. Nor should you use spaces in filenames. These are common mistakes new users make. Trying to map out Windows to Linux, directory for directory, is impossible. You can get as far as C:\ = / and maybe Default User = ~/, but beyond that you’re out of luck. Make sure new users understand that everything starts at / and their most important directory is their home directory (aka ~/ aka /home/USERNAME/).

9: Skipping updates

I have been burned with Windows updates many times. Need I bother mentioning the update from Explorer 7 to Explorer 8? Very rarely has a Linux update fubar’d a system of mine. In fact, I can’t remember the last time it has. So I am always up to date on my systems… and with good reason. Those updates bring new security patches and features to software and should be applied. Having an installation with a security hole is not what your users need, especially on a machine that houses important information.

10: Logging in as root

I really shouldn’t have to say this. But just in case, be sure to tell your users DON’T LOG IN AS ROOT! But… just in case they must… DON’T LOG IN AS ROOT! Instead, have them open up a terminal window and either “su” to root or use “sudo”. And just in case you didn’t hear me the first time, DON’T LOG IN AS ROOT!

11: Losing windows to the pager

The pager is one of the handiest features of the Linux desktops. But over and over, I’ve seen that new users don’t quite understand what the pager is for and what it does. Because of this, they will “lose” their windows from the desktop. Where did it go? It was there a moment ago! I guess it crashed. No. More than likely, they moved it to another desktop. Another desktop? You see where this is going? Help the new user understand what the pager is and how useful it can be.

12: Ignoring security because it’s Linux

A big part of me still wants to boast and say, “In the 12 years I have used Linux, I have never once had a virus or worm or been hacked.” Although that is true, it doesn’t mean I should ignore security. I have witnessed the effects of a rootkit on a Linux machine. They aren’t pretty and data will be lost. Tell your users that they can’t ignore security just because they’re using Linux. Security is crucial, regardless of the OS.

Been there?

We have all fallen victim to these types of mistakes at one point or another. But you can avoid them, and you can help other new users avoid them as well. Let’s all help to make Linux a better experience! If you’ve encountered other big Linux mistakes, share them with us.

Should you choose 32-bit or 64-bit Linux?

noreply@blogger.com (Arun Tom) — Tue, 05 Jul 2011 04:13:00 +0000

A common question that pops up from time to time is whether someone who has a 64-bit CPU (such as an AMD64 or an Intel EM64T) should download a 64-bit or 32-bit Linux distribution. Since these processors are capable of running either one at full native speeds, what are the advantages and disadvantages to both? Here I hope to address some common issues.

Speed - Without a scientific set of benchmarks this one is really hard to measure. Some people think one distribution "feels" faster than another while others disagree. Suffice to say that no one has yet to prove scientifically that the 64-bit versions of Linux available today are significantly faster in performance than their 32-bit counterparts. Most "64-bit" versions of software are actually just recompiled versions of the 32-bit code, with no optimization that would take advantage of the new features these chips offer and perhaps boost performance. If you're looking to use 64-bit because you think it will be a major improvement in speed, I would reconsider.

Compatibility - Not all software runs on 64-bit Linux. Although there have been 64-bit native Linux distributions for several years (a year before Microsoft Windows XP64, but I digress), the software community has yet to fully embrace the technology. As of the time this post was written, there is no 64-bit version of the Macromedia Flash Plug-in for your web browser, for instance. WINE and the Java VM have been known to cause problems on some 64-bit installations as well. Not all hardware has 64-bit drivers yet. The two major display card manufacturers (ATI and Nvidia) do have X86_64 versions of their drivers, but they are sadly the exception rather than the norm.

RAM - If you plan on using a machine that has more than 4GB of RAM, you'll need to use the 64-bit version of your distribution because 32-bit operating systems are only able to handle up to 4GB, maximum*. There's just not enough memory addresses for more. This is usually not a problem for desktop users, but it might be a concern for servers or high-end workstations.

The "coolness" factor - As Apple Computer has proven in recent years, there's an awful lot people will do just because something looks or feels "cool". This is perhaps the one reason why some people choose to run 64-bit Linux: it's a neat idea. To some people the idea of running a 64-bit native** operating system on their 64-bit CPU is just too cool to pass up. These people understand the drawbacks to running a bleeding-edge system and accept the extra work involved. If this describes you, more power to you.

So which should I choose? (29 July 2008) Over the last 2 years since I wrote this thread, a lot of progress has been made and I believe at this point that 64-bit Linux distributions are pretty much identical in performance and features as their 32-bit counterparts. I say "pretty much" because there's still no native Flash player. There are ways around that. I've not had issues with Java in 64-bit in recent months, so progress was made there too.

That being said, the point I make in the beginning still stands: although 64-bit Linux distributions are now by and large on-par with their 32-bit brethren, they do not yet surpass them in performance. You're not running at as much of a deficit with 64-bit two years later, but you still don't quite have an advantage either. Now, I think, rather than strongly suggesting 32-bit I could say either will work, but neither has any significant advantage over the other. It's more a matter of personal preference.

* NOTE: The 32-bit Linux kernel can be recompiled to handle up to 64GB of RAM if you're particularly concerned about staying 32-bit.

** NOTE: Although 64-bit Linux distributions do include a natively-compiled Linux kernel and several natively-compiled key applications, not every package in a 64-bit Linux distribution is 64-bit. The 32-bit library files and many 32-bit applications still exist and are used on a regular basis, so the idea that a 64-bit distribution is "native" is really a misnomer.

do you ever heard of a Live CD ?

noreply@blogger.com (Arun Tom) — Mon, 04 Jul 2011 20:00:00 +0000

Ubuntu 11.04 Beta 2 system running from a live CD,
with the new Unity desktop environment

A live CD, live DVD, or live disc is a CD or DVD containing a bootable computer operating system. Live CDs are unique in that they have the ability to run a complete, modern operating system on a computer lacking mutable secondary storage, such as a hard disk drive. Live USB ,flash drives are similar to live CDs, but often have the added functionality of automatically and transparently writing changes back to their bootable medium.

Origin of Linux live CDs

Although early developers and users of distributions built on top of the Linux kernel were able to take advantage of cheap optical disks and rapidly declining prices of CD drives for personal computers, the Linux distribution CDs or "distros" were generally treated as a collection of installation packages that must first be permanently installed to hard disks on the target machine.

However in the case of these distributions built on top of the Linux kernel, the free operating system was meeting resistance in the consumer market because of the perceived difficulty, effort, and risk involved in installing an additional partition on the hard disk, in parallel with an existing operating system installation.

The term "live CD" was coined because after typical PC RAM was large enough and 52x speed CD drives and CD burners were widespread among PC owners, it finally became convenient and practical to boot the kernel, run X11, a window manager and GUI applications directly from a CD without disturbing the OS on the hard disk.

This was a new and different situation for Linux than other operating systems, because the updates/upgrades were being released so quickly, different distributions and versions were being offered online, and especially because users were burning their own CDs.

The first Linux-based 'Live CD' was Yggdrasil Linux first released in beta form 1992~1993 (ceased production in 1995), though in practice its functionality was hampered due to the low throughput of contemporary CD-ROM drives. DemoLinux, released in 1998, was the first Linux distribution specially designed as a live CD.

The Linuxcare bootable business card, first released in 1999, was the first Live CD to focus on system administration, and the first to be distributed in the bootable business card form factor.

As of 2010, Finnix (first released in 2000) is the oldest Live CD still in production.Knoppix, a Debian-derived Linux distribution, was released in 2003, and found popularity as both a rescue disk system and as a primary distribution in its own right.

Since 2003, the popularity of live CDs has increased substantially, partly due to Linux Live scripts and remastersys which made it very easy to build customized live systems. Most of the popular Linux distributions now include a live CD variant, which in some cases is also the preferred installation medium.

Uses

While some live CDs are designed to "demo" or "test drive" a particular operating system (usually Linux or another free or open source operating system), there are live CDs made for many different uses.

Although some live CDs can load into memory in order to free the optical drive for other uses, loading the data off a CD-ROM is still slower than a typical hard drive boot, so this is rarely the default with large live CD images, but for smaller live CD images loading the filesystem directly into RAM can be highly practical. Loading the filesystem image into RAM can provide a significant performance boost as RAM is several orders of magnitude faster than a hard drive.

Also, since RAM has no moving parts, a system running from a live CD loaded into RAM can run with improved power efficiency.Experienced users of the operating system may also use a live CD to determine whether and to what extent a particular operating system or version is compatible with a particular hardware configuration and certain peripherals, or as a way to know beforehand which computer or peripheral will work before buying.

Users may also use a live CD to troubleshoot hardware, especially when a hard drive fails, and more generally as a recovery disc in case of problems. Some live CDs can save user-created files in a Windows partition, a USB drive, a network drive, or other accessible media.

A few additional uses include:

installing a Linux distribution to a hard drive
testing new versions of software
listing & testing hardware
system repair and restoration
high security/non-invasive environment for a guest
cracking/stealing passwords
network security testing
being the primary or backup operating system for any computer
quick and simple clustering of computers
computer forensics
playing video games
providing a secure server platform where crucial files cannot be permanently altered
providing a secure, reliable platform for the performance of high-vulnerability tasks such as internet banking;
Internet kiosks, which can be brought back to their original state by a reboot

Thematic Live CDs

Several live CDs are dedicated to specific type of applications according to the requirements of thematic user communities. These CDs are tailored to the needs of the applications in subject including general knowledge, tutorial, specifications and trial data too.

Some of these topics covers sub topics, e.g. IT administration breaks down to firewall, rescue, security, etc. type of live CDs. In some cases a particular LiveDVD covers more than one topic.

Live CD software appliances

Packaging a software appliance as an installable live CD can often be beneficial as a single image can run on real hardware in addition to most types of virtual machines.

This allows developers to avoid the complexities involved in supporting multiple incompatible virtual machine images formats and focus on the lowest common denominator instead.

Typically after booting the machine from the live CD, the appliance will either run in non-persistent demo mode or install itself, at the user's request, to an available storage device.

Mounting without burning

The files on a live CD ISO image can be accessed in Microsoft Windows with a disk image emulator such as Daemon Tools, or in Unix variants by mounting a loop device.

After mounting the live CD's filesystem, software on the live CD can be run directly (I.e., without booting) by chrooting into the live CD's mounted filesystem.

A live CD ISO image can also be mounted by Virtual Machine software such as VirtualBox and VMware Workstation or can be converted to a Live USB using SYSLINUX. Tools such as UNetbootin can automate this process.

Common traits

Some live CDs come with an installation utility launchable from a desktop icon that can optionally install the system on a hard drive or USB flash drive. Most live CDs can access the information on internal and/or external hard drives, diskettes and USB flash drives.

Generally live CDs are booted from read-only media, requiring either copying to rewriteable media (i.e. a hard drive) or complete remastering to install additional software; however, there are exceptions such as Puppy Linux which has the ability to save files to the live CD itself or other multisession media, allowing users to carry data, and more importantly, added programs and customized settings, along with them on optical disc.

Most live CDs are based on Linux,

as this was the operating system that had the most to gain by offering free trials and demonstrations without regard to sales or copyright. Now others are using the term live CD for other operating systems, such as

OpenSolaris, BeleniX and others based on Solaris. Other "live" operating systems include AmigaOS 4, FreeBSD, FreeDOS, Mac OS, Microsoft Windows, OS/2, ReactOS, NetBSD, OpenBSD, MINIX 3, Plan 9 from Bell Labs, and MorphOS.

The first personal computer operating system on a CD to support "live" operations might have been the AmigaOS, which could be booted from CD on an Amiga CDTV in 1990.

Earlier examples of live OS are of course the operating systems used from floppy, and most widely spread is DOS.

Unlike previous operating systems on optical media, though, Linux and OS/2 "live CDs" were specifically designed to run without installation onto other media like a hard disk drive. The live CD concept was meant to promote Linux and showcase the abilities of the free, open source operating system on conventional personal computers with Microsoft Windows already installed.

On a PC, a bootable Compact Disc generally conforms to the El Torito specification. Many Linux based live CDs use a compressed filesystem image, often with the cloop compressed loopback driver, or squashfs compressed filesystem, generally doubling effective storage capacity, although slowing application start up

The resulting environment can be quite rich: typical Knoppix systems include around 1,200 separate software packages. Live CDs have a reputation for supporting advanced auto-configuration and plug-and-play functionality. This came out of necessity to avoid requiring the user to configure the system each time it boots and to make it easily usable by those who are new to the operating system.

Technique

A read-only file system, such as on a CD-ROM has the drawback of being unable to save any current working data. For this reason, a read-only file system is often merged with a temporary writable file system in the form of a RAM disk. Often the default Linux directories "/home" (containing users' personal files and configuration files) and "/var" (containing variable data) are kept in ramdisk, because the system updates them frequently. Puppy linux has a savable layer so if you choose to, the next time you boot you can resume (pick right back up again) from where you left off. Each time the CD boots, it looks for the file and then uses it if it has the right name.

In modern live CDs, a read-only file system is merged with ramdisk using transparent techniques such as UnionFS, AuFS or EWF. In MS-DOS and OS/2 systems, ramdrive.sys, can be loaded at boot for this purpose. Boot loaders like syslinux can boot ISO files from USB memory devices.

Live CDs have to be able to detect and use a wide variety of hardware (including network cards, graphic cards etc.) in realtime. This is easily achieved nowadays by udev, hotplug, hal, udisk etc.. which is a common part of all distributions based on Linux kernel 2.6.

Boot code

During live CD initialization, a user typically may resort to using one or more boot codes to change the booting behavior. These vary from distribution to distribution but can most often be accessed upon first boot screen by one of the function keys.