We can find out the reason behind application slowness by analyzing the Thread Dump in Java world. Thread dumps are also very useful to analyze and troubleshoot performance related issues such as server hang, deadlocks, slow running, idle or stuck applications, slow database interactions etc.

The thread dump is a snapshot of exactly what’s executing at a moment in time.

Following are various method we can try to collect the thread dump in weblogic

WebLogic Server (WLS) and Java offer several ways to generate thread dumps, which are listed below in order of preference. It is always better to obtain the thread dumps by using operating system (OS) commands rather than by using Java classes or the Administration Console, because if the console is hanging, users won’t be able to connect to it to issue thread dumps.

Method 1. Use operating system commands to get the thread dumps when WLS starts up from a command-line script:
On Windows OS, thread dumps can be created by

<ctrl>+<break> in console -- the thread dumps are generated in the server stdout

On POSIX-compliant platforms (e.g. Solaris and Linux), first identify the process ID (pid) using

ps -ef | grep java

then run

kill -3 <pid> 2>&1

Signal 3 is equivalent to SIGQUIT. Note that in Solaris, the thread dump is generated in the current shell, but in Linux, the thread dump is generated in the shell which started the java process specified by the pid.

Method 2. Using beasvc:

beasvc -dump -svcname:<service_name> -log:<td_pathname>

service_name is the Windows service that is running the server instance (e.g.mydomain_myserver)
td_pathname is the full path and the name of the file in which the thread dump will be generated into

Method 3. Using weblogic.WLST:

java weblogic.WLST
connect("<username>","<password>","t3://<url>:<port>")
threadDump()

The thread dump will be generated in Thread_Dump_AdminServer.txt.

Method 4. From a command line or shell, a thread dump can be generated via the following command (deprecated from WLS 9.0):

java weblogic.Admin <url>:<port> -username <username> -password <password> THREAD_DUMP

The thread dump will be generated in the defined server stdout.

Method 5. From the WLS Administration Console, a thread dump can be created by navigating to
Server -> -> Monitoring -> Dump threads stack.
This method could lead to truncated or incomplete thread dumps.

Method 6. From the JRockit command line:

jrcmd <pid> print_threads

In cryptography, a cipher is an algorithm for performing encryption or decryption i.e a series of well-defined steps that can be followed as a procedure. In SSL cipher suits are responsible for encryption.

To configure SSL in Weblogic follow this post

In Weblogic Application Server by default following ciphers are supported

Cipher Suite : TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA
Symmetric Key Strength (Bits): 168

Cipher Suite : TLS_DHE_RSA_WITH_DES_CBC_SHA
Symmetric Key Strength (Bits): 56

Cipher Suite : TLS_DHE_RSA_EXPORT_WITH_DES40_CBC_SHA
Symmetric Key Strength (Bits): 40

Cipher Suite : TLS_DH_anon_WITH_3DES_EDE_CBC_SHA
Symmetric Key Strength (Bits): 168

Cipher Suite : TLS_DH_anon_WITH_RC4_128_MD5
Symmetric Key Strength (Bits): 128

Cipher Suite: TLS_DH_anon_WITH_DES_CBC_SHA
Symmetric Key Strength (Bits): 56

Cipher Suite : TLS_DH_anon_EXPORT_WITH_RC4_40_MD5
Symmetric Key Strength (Bits): 40

Cipher Suite : TLS_DH_anon_EXPORT_WITH_DES40_CBC_SHA
Symmetric Key Strength (Bits): 40

Cipher Suite : TLS_DHE_RSA_EXPORT_WITH_DES_40_CBC_SHA
Symmetric Key Strength (Bits): 40

Cipher Suite : TLS_DH_anon_EXPORT_WITH_DES_40_CBC_SHA
Symmetric Key Strength (Bits): 40

Cipher Suite : TLS_RSA_WITH_RC4_128_SHA
Symmetric Key Strength (Bits): 128

Cipher Suite : TLS_RSA_WITH_RC4_128_MD5
Symmetric Key Strength (Bits): 128

Cipher Suite : TLS_RSA_WITH_DES_CBC_SHA
Symmetric Key Strength (Bits): 56

Cipher Suite : TLS_RSA_EXPORT_WITH_RC4_40_MD5
Symmetric Key Strength (Bits): 40

Cipher Suite : TLS_RSA_EXPORT_WITH_DES_40_CBC_SHA
Symmetric Key Strength (Bits): 40

Cipher Suite : TLS_RSA_EXPORT_WITH_DES40_CBC_SHA
Symmetric Key Strength (Bits): 40

Cipher Suite : TLS_RSA_WITH_3DES_EDE_CBC_SHA
Symmetric Key Strength (Bits): 168

Cipher Suite : TLS_RSA_WITH_NULL_SHA
Symmetric Key Strength (Bits): 0

Cipher Suite : TLS_RSA_WITH_NULL_MD5
Symmetric Key Strength (Bits): 0

Cipher Suite : TLS_RSA_EXPORT1024_WITH_DES_CBC_SHA
Symmetric Key Strength (Bits): 56

Cipher Suite : TLS_RSA_EXPORT1024_WITH_RC4_56_SHA
Symmetric Key Strength (Bits): 56

Cipher Suite : TLS_RSA_WITH_AES_128_CBC_SHA
Symmetric Key Strength (Bits): 128

Cipher Suite : TLS_RSA_WITH_AES_256_CBC_SHA
Symmetric Key Strength (Bits): 256

In the above list there are some cipher which are vulnerable. To close this ciphers we have do following:
Step 1 Stop weblogic Admin / Managed Server

Step 2 Go to Domain Home
For eg
cd /app/Oracle/Middleware/user_projects/domains/vidyadhar/

Step 3 Now we have to modify config file.

cd /app/Oracle/Middleware/user_projects/domains/vidyadhar/config

First we will take a backup of existing config.xml file

cp config.xml config.xml.orig

Step 4 To disable weak ciphers you have to add following under ssl tag in config.xml

<ciphersuite>TLS_RSA_WITH_RC4_128_SHA</ciphersuite>
<ciphersuite>TLS_RSA_WITH_RC4_128_MD5</ciphersuite>

See the screenshot for better understanding

In my scenario I am having only single Admin Server which is running on https 7002 port. If you have managed server which is running on https port then you have to add above values in the SSL tag of managed server also.

Step 5 Now do the start the weblogic services.

You can test the cipher suites using SSLDigger

Officially IBM do not support installing Websphere Application Server (WAS) on Ubuntu. There are so many user like me who just want to evaluate the product by installing it on their desktop OS.

This is a how-to for installing IBM Websphere Application Server 7 on Ubuntu 11.10

Please Note : I have reduced the screen shots size. For better viewing click on the screenshots.

First download Websphere Application Server Trial binaries for linux from here and save it to /tmp/ folder

Before going ahead we have to run following commands for smooth installation on Ubuntu as Ubuntu is not a certified OS to install Websphere Application Server

sudo -i
cd /bin
unlink sh
ln -s /bin/bash sh

I am going to install WAS through vidyadhar user and will be installting WAS in /app/IBM folder. So first I will create /app/IBM folder

sudo mkdir -p /app/IBM
sudo chown -R vidyadhar:vidyadhar /app/IBM

Uncompressing the Binary files and starting the installation

cd /tmp/
mkdir WAS_INSTALLABLES
cd WAS_INSTALLABLES
tar zxvf ../was.cd.70011.trial.base.opt.linux.ia32.tar.gz
cd /tmp/WAS_INSTALLABLES/WAS
./install

Step 1 Installation wizard welcome screen
You will be presented with the installation wizard welcome screen as seen below:
Clicking on Next will take you to the software license agreement screen.

Step 2 Software license agreement
It is a requirement that you accept the license agreement; Click Next to move on to the prerequisites check.

Step 3 System prerequisites check
The installer will check to ensure that your Linux OS meets the required prerequisites. If your OS is not supported, you may see a screen similar to the one below:

Step 4 Non root user warning
As we are not using root user to install WAS we will see the below warning. Click Next to bypass the same.

Step 5 Optional features
In this option we can install Sample Applications, Language Pack. For my installation it is not needed so I am just deselction all the options.

Step 6 Installation directory
We are doing this installation in /app/IBM directory.

Step 7 WebSphere Application Server environments
Depending on which installation scenario you chose, you will now have to select a type of installation. The type of installation chosen will determine whether a profile is created or not.
There are three types of installation options listed by the wizard as shown below:

Management profile
A management profile includes an administrative agent server and services for managing multiple application server environments. An administrative agent manages application servers that are on the same machine.

Standalone application server
A standalone application server environment runs your enterprise applications. The application server is managed from its own administrative console and functions independently of all other application servers.

Base binaries
WebSphere Application Server version 7.0 requires at least one profile to be functional. Select this option only if one or more profiles will be created after installation completes successfully.

In this installation I do not want to create any profile so I am selection None option

Step 8 Profile Warning
As we are selecting NONE profile it will give following error. Click NEXT

Step 9 Verifying Permission
In next screen select Verify my permission to perform the installation to avoid installtion errors.

Step 10 Verifying Permission
In this screen you will get Success message for permission, click on NEXT to go ahead.

Step 11 Installation Progress Screen

Step 12 Installation Complete
In case of successfull installation you will see Success message on the screen. I have unchecked Profile Creation Wizard option

I have also posted the video tutorial on Youtube

Today one of our client has forgot his Application Server Console password. We have used following method to reset his password.

Please Note : This method also work on following

• Oracle Fusion Middleware Version 9.0.4.0.0 to 10.1.3.5.0
• Enterprise Manager Base Platform Version 10.1.0.2 to 10.2.0.5
• Enterprise Manager for Fusion Middleware Version 9.0.4.0.0 to 10.1.3.5.0

Step 1 First shutdown the application server control by running emctl command
For 10.1.2

$ORACLE_HOME/bin/emctl stop iasconsole

On 10.1.3 you need to stop the OC4J instances before performing the password change:

$ORACLE_HOME/opmn/bin/opmnctl stopproc ias-component=OC4J

Step 2 Locate and backup the jazn-data.xml (10.1.2) or system-jazn-data.xml (10.1.3) file:
On 10.1.2 File Location would be

$ORACLE_HOME/sysman/j2ee/config/jazn-data.xml

On 10.1.3 File Location would be

$ORACLE_HOME/j2ee/home/config/system-jazn-data.xml

Step 3 Edit the jazn-data.xml / system-jazn-data.xml file depending on the Application Server version in a text editor and locate the line that defines the credentials property for the ias_admin user:

On 10.1.2
The following example shows the section of jazn-data.xml with the encrypted credentials entry in boldface type:

<realm>
     <name>enterprise-manager</name>
      <users>
       <user>
        <name>ias_admin</name>
         <credentials>rJqp85BkhFwAyw9ddl0PnFlUBVaWzbfT</credentials>
       </user>

On 10.1.3
The following example shows the section of system-jazn-data.xml with the encrypted credentials entry in boldface type:

<realm>
  <name>jazn.com</name>
   <users>
    <user>
      <name>oc4jadmin</name>
      <display-name>OC4J Administrator</display-name>
      <description>OC4J Administrator</description>
       <credentials>{903}4L50lHJWIFGwLgHXTub7eYK9e0AnWLUH</credentials>
    </user>

Step 4 Replace the existing encrypted password with the new password
Be sure to prefix the password with an exclamation point (!). For example:
!mynewpassword123

Step 5 Start the Application Server Console:
For 10.1.2 do following

$ORACLE_HOME/bin/emctl start iasconsole

After the restart, the Application Server Control will be using your new Administrator (ias_admin) password, which will be stored in encrypted format within the jazn-data.xml file.

For 10.1.3 do following

$ORACLE_HOME/opmn/bin/opmnctl startproc ias-component=OC4J

After the restart, the Application Server Control will be using your new Administrator (oc4jadmin) password, which will be stored in encrypted format within the system-jazn-data.xml file.

Step 6 Login to the Application Server Console and authenticate with the ias_admin user (10.1.2) or the oc4jadmin user (10.1.3) and the new password.

LibreOffice is the free power-packed Open Source personal productivity suite for Windows, Mac and Linux, that gives you six feature-rich applications for all your document production and data processing needs: Writer, Calc, Impress, Draw, Math and Base. Support and documentation is free from our large, dedicated community of users, contributors and developers.

Recently LibreOffice team has released LibreOffice 3.5 RC 1. In this tutorial we will see how to install LibreOffice 3.5 RC 1 on Ubuntu

Step 1 Go to LibreOffice official website and download the LibreOffice 3.5 RC 1 archive for Ubuntu

cd /tmp/vidyadhar
wget http://download.documentfoundation.org/libreoffice/testing/3.5.0-rc1/deb/x86/LibO_3.5.0rc1_Linux_x86_install-deb_en-US.tar.gz
tar zxvf LibO_3.5.0rc1_Linux_x86_install-deb_en-US.tar.gz

Step 2 To install LibreOffice 3.5 RC 1 you have to run dpkg command

cd /tmp/vidyadhar/LibO_3.5.0rc1_Linux_x86_install-deb_en-US/DEBS
sudo dpkg -i *.deb
cd desktop-integration
sudo dpkg -i *.deb

That’s it. Enjoy your LibreOffice 3.5

In this guide we will upgrade the Ubuntu kernel version. By default Ubuntu 11.10 ships with 3.0 Kernel version. We will install the new kernel 3.2 over existing 3.0

Step 1 First we will see the current kernel version. To do so run following

uname -r

Output will be something like below

Step 2 Now we will add kernel ppa. Open a command propmt and run following commands

sudo add-apt-repository ppa:francisbrwn9/kernels
sudo apt-get update
sudo apt-get dist-upgrade

Step 3 Once finish, you have to reboot your machine to use the newest kernel. After reboot run uname -r to see the kernel version

uname -r

Output will be something like below

Enjoy your new Kernel

Oracle Application Server is no longer available. The reason is because once “Oracle SOA Suite 10g (10.1.3.1.0)” was released, it contains the same product features and functionality, including some features which are not obtainable without the 10.1.3.1 media. In this tutorial we will see how to install Oracle Application Server 10g R 3(10.1.3.X) on Windows.

Requirements
Windows OS
Oracle Application Server 10.1.3.X

Step 1 Downloading Oracle Application Server 10.1.3.X
Oracle provides 32-bit and 64-bit versions of Oracle Application Server for Windows. The 32-bit version runs on Intel x86, AMD64, and Intel EM64T processors. For additional information, visit OracleMetaLink at http://metalink.oracle.com

I have downloaded the installer files at C:\Downloads\INSTALLABLES\Oracle For 32 bit installer file name would be soa_windows_x86_101310_disk1.zip

I have extracted the same to C:\Downloads\INSTALLABLES\Oracle

Step 2 Starting the installation
Go to extracted folder. In our case it is C:\Downloads\INSTALLABLES\Oracle\soa_windows_x86_101310_disk1\soa_windows_x86_101310_disk1 and double click on setup.exe It will start the Oracle Application Server Universal installer

Step 3 Oracle Application Server 10g 10.1.3.X screen
Enter the installation directory where you want to install Oracle Application Server. In our case I choose D:\product\10.1.3.1\OracleAS_1 Also select Advance Installation mode.

For the Warning please click on yes

Step 4 Select Installation Type screen
In this section choose J2EE server and Web server, as we are going to use only oc4j containers for J2EE and HTTP Server

Step 5 Specify Port Configuration Options screen
In Specify Port Configuration Options screen Select Automatic and click Next

Step 6 Administration Instance Settings screen
In AS administrator settings enter following values:
AS instance Name : techienote
AS Administrator Password : admin_123
OC4J Instance Name : home
Select Configure this as an Administration OC4J instance. This will start EM console as soon as you start the oracle service via OPMN.
Click Next.

Step 7 Cluster Topology Configuration screen

Deselect Configure this instance to be part of an Oracle Application Server cluster topology as this is a simple installation and click on Next

Step 8 Now it will start the installation process

Step 9. Configuration Assistant
At this level installer will configure various service. In case of any failure please see installation logs which are located at C:\Program Files\Oracle\Inventory\logs folder

Step 10 End of Installation
On this screen you will get Oracle Application server EM console URL

Step 11. Access the Oracle Application Server Welcome page to verify that the installation was successful. The URL for the Welcome page is:

http://hostname.domainname:http_port

You can locate the URL for accessing the Welcome Page on the End of Installation Screen text, which is stored in the following file:
ORACLE_HOME\install\readme.txt

The Welcome page provides links to these useful pages:
New features in Oracle Application Server 10g Release 3 (10.1.3)

• Oracle Enterprise Manager Application Server Control (“Application Server Control”), which is a browser-based administrative tool
• Release Notes
• Quick Start
• Demos

That’s it. You are ready with the application server installation. In next section we will see how to deploy sample application in Oracle Application Server.

Bejeweled is very popular game for PalmOS / Windows / Java based phone. Now you can also play the same game on your Ubuntu desktop by installing Gweled. Gweled is a GNOME version of Bejeweled or Diamond Mine.

The aim of the game is to make alignment of 3 or more gems, both vertically or horizontally by swapping adjacent gems. The game ends when there are no possible moves left.

Here’s how to install and play Gweled on Ubuntu:

Step 1 Issue the following command at the terminal

sudo apt-get install gweled

Step 2 After the installation is complete, go to Menu > Games > Gweled to start the game. Else type gweled in console.

That’s it. Enjoy your game.

In the smartphone market android os is the best OS I have used till now. Android was listed as the best-selling smartphone platform worldwide in Q4 2010 by Canalys. Android is capable of wide variety of functions due to its openness, but a lot of the problems comes from a lack of understanding of the OS.

Because of the way memory is managed in the Android OS, and the way Android apps are structured, the more apps you load, the less memory is available to actually run the apps. The less memory is available, the slower the phone will run, as the phone must spend more time swapping apps in and out of the little working memory available. This affects both battery life and performance.

The problem shows itself in at least three ways:

Symptom 1: You download an updated app and the download stops for apparently no reason

Diagnosis: The “downloading service” was shuffled out by the system, killing the download.

Go the the “services screen”. (see below) Does the “download service” says “restarting” to the right? That means It was indeed stopped by the system to give the memory to some other apps.

Symptom 2: Apps used to load from the launcher instantly now takes several seconds. Screens transitions are slow as heck. Loading a new supposedly “fast” launcher did not help.

Diagnosis: System is busy shuffling various activities and services in and out of memory.

Does lot of different services show “restarting”? Do the some of the services shows very short “active life”?

Symptom 3: Your phone used to last most of a day but now it won’t last past lunch without a charge

Diagnosis: You have all sorts of services in the background using battery power here and there

If you go into the battery usage screen (settings > About Phone > Battery Usage) and you see a very long list of apps all taking a few bits and pieces of power, you have too many apps loaded, and they are all sucking up a little power, and all those bits and pieces add up.

All these problems can be traced back to a single cause: too many apps in too little memory. However, as the memory in Android phones are not expandable, you can only deal with the problem by remove apps to make more memory available. But first, let us dig into the Android OS and learn how Android OS manages memory.

So How Android OS Really Manages Memory?

The Android OS memory management is a complicated subject, and is quite technical.
Android OS roughly groups all apps into 6 groups, with priority from highest to lowest:
Foreground app: you see this app on screen, currently running, but also includes the system itself and “phone”

Visible app: the app is running and visible, but due to multi-tasking or such is not currently “on top”

Secondary server: services that stay in background and apps such as Launcher (or other home replacements). Most services go here, like music player, clock updater, background sync, and so on, that’s not built into the OS.

Hidden Application: apps not visible, but still running in the background

Content Provider: process that provides content to the foreground, such as “contacts content provider”, “calendar content provider”, and so on. May also known as “storage”.

Empty App: the app is in standby, not being used, but is still in memory

Within each ‘group’ the system assigns a “priority” number based on how recently the app was accessed, with assumption that a most recently access program should be kept, and the oldest will be out of luck.

When Android OS runs out of free memory and needs to load a new app, it starts killing apps in Empty App group, oldest first. if that’s not enough, it then starts killing apps in the Content Provider Group, and it keeps going up groups until it has finally freed up enough memory to load the app and all related processes (such as services).

NOTE: Having a constant “notification” in the notification area makes the program “visible app” instead of “hidden app”, thus making it less likely to be killed by the system to make room for other apps.
Most of the problems occur when the system tries to make room by killing “secondary server” processes that are needed.

Never Enough Memory

Android OS has THREE main pools of memory: RAM (for running programs), app storage (for storing programs that will be ran) and finally, SD card (for storing data like music, photos, and secondary storage). (NOTE: Some phones have “internal” SD card and external SD card, and they are known as /sdcard and /sdcard-ext respectively.)

RAM management is very complicated because Android OS is based on a Linux kernel (read: heart) and even seasoned Linux developer will tell you it is virtually incomprehensible. After extensive experimentation, it is found that the hardware itself (i.e. the PHONE) will take 32MB or so even before the Android OS loads. Then the fixed components like “system” (acore, phone, gapps, system…) will take up about 65-80MB. That’s about 100-128 MB gone, without a single actual app being loaded.

Then you load the launcher itself, which uses anywhere like 8-30 MB.

Now the individual apps load, except it’s not that simple. Many apps have several components, the frontend (user interface) called “process”, and the backend (“services”). Due to the way the apps work under the Android OS they usually take up at least 3 MB of RAM even though the app itself appears to be only a few hundred KB in size. Some can use a lot more RAM.

Check the Services screen. You will see each service takes up 2-5 (or more) MB, some may take 15 or more. That does not leave much for the apps, esp. when the “services” are often loaded automatically. The more apps you load (or start automatically), the less is available to the system.

Every widget you place on the screen is backed up by a service. If you have 5 widgets on screen, that’s another 20 MB or so gone. Subtract another 10-20 for live wallpaper (depending on complexity), and your consumed RAM is up to 160+ MB, and that’s BEFORE you actually run any programs!

The early Android phones are extremely RAM deficient. Original Google phone, the T-Mobile G1 has only 192MB internal storage, and original Motorola Droid has only 256MB. With 16)+ MB used up before any apps, this leaves almost NOTHING for the actual apps. The later Android phones like Samsung Galaxy S series expanded that to 512MB, and some of the latest phones are up to 768MB or even 1 GB in RAM. So keeping more internal memory free is easier on those phones.

So you’re probably wondering, if there’s only like 80-90MB of RAM available, how can you load like 100-200 MB of apps? What happens is the phone try to fit in more apps than the memory would allow, so it kills off “lower priority” apps and services in order to make room for other apps. However, those apps may request the system to load itself back into memory, so you have a CPU trying to fit X+Y programs into space that can only fit X, by time-sharing… Load apps to do something, then swap those out of memory and swap some others back in. This constant swap process is handled all in the background.

NOTE: The way system decides what to kill and what to load is rather complicated, so see the sidebar.

So the lesson learned is simple: load LESS stuff into RAM. And how do you load less stuff into RAM? Load less apps. Really, it is that simple.

Your App storage is important, but not as important as RAM. My phone shows I’ve used up 176MB of my 256MB of app storage just for apps and their cache and data. Each app you load also needs some space to store working data. So a small app of only a few hundred KB can be using several megabytes of data, both working data and cache. Web browser apps are notorious for keeping cache of several megabytes when it is only a few hundred KB in size.

To see how much app storage you got left, go to menu / Settings / Sd Card and Phone Storage. At the very bottom, under “internal Phone stroage”, it’ll tell you how much it has left.

So what can we do about this? Here are 6 normal tips and 4 advance tips.

Tip 1: Uninstall the apps you rarely use

It is obvious, but it’s still true: the less program you load, the more responsive the phone will be, because there are a LOT of free memory available. More memory will be available to the phone to actually RUN the programs.

If you want to save the app, use something like AppManager, AppMonster, or Titanium Backup to archive the apps you want to keep around to SD card. Or just redownload them when you need them.

Figure out which apps are taking up the most space by going to menu / Settings / Applications / Manage Applications / menu / sort by size (default is sort by alpha A-Z)

(You can also sort by size in AppBrain, but that’s the “total size”, not the “internal storage size”, which is not that useful)

Also see Tip #6: Do NOT use a Task Killer.

Tip 2: Move apps back from SD Card… if possible

(Yes, I know I used to recommend the exact opposite)

Apps are really meant to be run from internal storage. Move2SD is a neat feature, but SD card is still not as fast as internal storage (unless you have a Class 10 or faster). For the apps you use often, move them BACK INTO phone. They’ll actually run faster.

Tip 3: Use only the bare minimum number of widgets

Each widget loads a “service” or two to keep itself updated, and each service is 2-4 MB of space used, even if the widget itself is only like 50KB in size.

Look at the Services Screen yourself: How much is that pretty clock widget taking up? Probably 2-4 MB. Add another one for the music player, another one for the podcast player, another one for this, another one for that… They all add up.

Tip 4: Use a Static Wallpaper

Even a simple Live Wallpaper will take 2 MB or so of memory. Complicated ones may take up to 20MB. And that thing is running ALL THE TIME. It even sucks up CPU power (and battery). Thus, just use a static wallpaper.

Tip 5: Occasionally, Manually Kill Unnecessary Services

Seems every app nowadays comes with a service… and uses several MB of internal memory, even when they are NOT running.

Google Maps have a “Places” service that sometimes loads even when Maps is NOT loaded. Youtube sometimes loads a “widget service” even when it’s not running and have no widgets on screen. When you exit an app, the associated services are not always stopped with it.

Kill them manually (see “Running Services” sidebar above), tap any service to kill it. Make their space available to other apps. In fact, if you rarely use that app, uninstall it altogether. (See Tip #1)

Tip 6: Do NOT Use Task Killers on Automatic or Schedule

Advanced Task Killer and similar apps may interfere with the built-in memory management. The memory they free up is only temporary and may include running apps, which will be reloaded by the system in moments.

The best way NOT to overburden the system is to load less apps in the first place

You can have one loaded, but turn off any auto-kill or schedule-kill functions. Advanced Task Killer for Froyo by ReChild is what I use, but only very occasionally, and you can just go into services and kill individual services.

For more information on why NOT to use Task Killers, see my other hub: Android OS Task Killers.

Advanced Tips for Rooted Phones

The following advanced tips all require rooting the phone, which means you gain “superuser” status that allows you to read/write all portions of the phone, even the “system” sections, which normal users don’t have access to. Not all phones can be rooted, and rooting your phone MAY void your warranty. You do so at your own risk, and there are guides out there on how to root your phone. If the 6 tips above are somehow not enough to help you, try the four tips below.

Advanced Tip 1: Use AutoStarts or Autorun Manager to disable automatic startup of programs

REQUIRES ROOT!

The good apps can be set to NOT run at startup. The not-so-good ones just start without giving you a choice.

Use AutoStarts (paid app) or Autorun manager (free) and disable the startups of certain apps. Not all apps need to stay on all the time. AutoStarts can also prevent apps from being started by certain system events, such as “bluetooth on”. For example, if you have an app that’s supposed to be triggered by the camera button, but isn’t, the only way you’ll diagnose it is run AutoStarts and see which app is hooked into that event and disable it.

There are a lot of programs that claims to stop “autorun” or “autostart”, but this is the original, and it really does work. The ones that don’t require root only works about half of the time.

Advanced Tip 2: Use Auto Memory Manager or AutoKiller to tweak settings

REQUIRES ROOT!

Use Auto Memory Manager or AutoKiller to tweak the built-in memory manager to be more aggressive or just somewhat more active (i.e. “mild”) than the default setting, which is VERY conservative.

This means you don’t need to mess with a task killer at all (except for certain instances). I have mine set on “mild”.

Advanced Tip 3: Load an Overclocked Kernel

REQUIRES ROOT!

Load an overclocking kernel so you can overclock the CPU in your Android phone. The OMAP CPU in the original Moto Droid is designed for 600 MHz, but is clocked at only 550 MHz for better battery life. However, it can be easily overclocked to 800 MHz without modification, and perhaps even 1.2 or 1.25 GHz (depending on how lucky you are) by loading a new kernel.

Keep in mind there are dozens of different alternate kernels out there and they are written for a specific phone model and specific clock speed. You will need to know how to boot into “recovery mode” in case your kernel experimentation did not work out.

I have mine set to 1.1 GHz and it never had any problems.

Advanced Tip 4: Load a new Custom ROM altogether

REQUIRES ROOT!

People love Customs ROMs, and many are noticeably faster (though a lot of it is from completely wiping out all the apps). Still, it is a valid way to “start over” with your phone.
For almost every model of Android phone (at least the popular ones) there are custom ROM developers making custom ROMs for it. The original Motorola Droid, i.e. OG Droid, had a dozen or more custom ROMs, the best known of which: Cyanogen Mod (which gradually expanded to support over a dozen different phones). However, there’s also Liquid, Alfonso, MIUI, and many more.

Following is the tutorial for installing Oracle VM server through PXE.

Requirement
PXE Server
Oracle VM Server 3.0.2

Step 1 Download & Mount OracleVM-Server.iso

mount -o loop /storage/os/OracleVM-Server-3.0.2.iso cd/

Step 2 Create folder to store oracle vm files.

mkdir -p /tftpboot/images/oraclevm/

Step 3 Copy required files to oraclevm folder under pxe.

cp cd/isolinux/mboot.c32 /tftpboot/images/oraclevm/
cp cd/isolinux/initrd.img /tftpboot/images/oraclevm/
cp cd/isolinux/vmlinuz /tftpboot/images/oraclevm/
cp cd/isolinux/xen.gz /tftpboot/images/oraclevm/

Step 4 append following lines in /tftpboot/pxelinux.cfg/default

LABEL ovs3
kernel images/oraclevm/mboot.c32
append images/oraclevm/xen.gz --- images/oraclevm/vmlinuz --- images/oraclevm/initrd.img

Thats all, now with pxe boot you’ll find option to boot using ovs. Once you boot from ovs pxe, you need to either give path of iso image using nfs store OR give http path where content of cd is copied / cd mounted.

Source @LINUXREADERS