Diploma in Information Technology and Operating System

What is Computer ?

2011-12-23T09:54:00.000+08:00

Introduction to Computers

An electronic device for storing and processing data, typically in binary form, according to instructions given to it in a variable program.

NEC Notebook

Examples of computer is laptop, notebook, netbook and desktop.

It responds to a specific set of instructions in a fast and accurate processed.

Computer are divided into two parts, that is :

Hardware
Software.

Hardware is the parts that you can touch like monitor, mouse, keyboard, speaker, printer and CPU(Central Processing Unit)

Software is the parts inside the computer like data, programs and operating system(for example Windows and Linux).

Philips Monitor

Pleomax USB Optical Mouse

Central Processing Unit (CPU)

Sonigear Speaker


Pleomax Keyboard

AVF USB Optical Mouse

Lenovo ThinkServer TS130

2011-10-20T10:24:00.000+08:00

Guided and Unguided Transmission Media

2011-09-27T11:24:00.000+08:00

ASSIGNMENT

Data Communication & Networking

IT 703(08)

The transmission media that are used to convey(pass on) information can be classified as guided or unguided. Guided media provide a physical path along which signal is propagated(travel through the air); unguided media employ an antenna for transmitting through air, vacuum, or water. Discuss both classify transmission media in detail by providing with example

Answer:

Physical media fall into two categories: guided media and unguided media. With guided media, the waves are guided along a solid medium, such as a fiber-optic cable, a twisted-pair coppeer wire, or a coaxial cable. With unguided media, the waves propagate in the atmosphere and in outer space, such as in a wireless LAN or a digital satellite channel.

Physical link like copper wire, fiber-optic cable and others which are called guided media is relatively minor compared with other networking costs, but the labor cost associated with the installation of this guided media is relatively high. So usually, many builders install twisted pair, optical fiber, and coaxial cable in every room in a building, eventhough if only one medium is initially used, there is a good chance that another medium could be used in the near future, and so money is saved by not having to lay additional wires in the future.

Twisted-Pair Cable such as the copper wire is the most common type of telephone line. It consists of two conductors, usually copper, each with its own plastic insulation, twisted together. One of the wires is used to carry signals to the receiver, and the other is used only as a ground reference. The wires are twisted to avoid the electromagnetic inteference (EMI). Twisted wires decrease the interference cause by the loop between the wires and it also reduce transmission errors by eliminating interference from nearby wires. The wires developed with coppers help to create a faster signal transmission. Although twisted-pair cable usually is used by older telephone networks and is the least expensive type of local-area network (LAN) cable, most networks contain some twisted-pair cabling at some point along the network.

There are two types of twisted pair wires:

Unshielded Twisted-Pair Cable (UTP)
Shielded Twisted-Pair Cable (STP)

UTP cable is one of the most common cable used in computer networking. UTP cables are often called ethernet cables. Twisted pair cabling is often used in data networks for short and medium length connections because of its relatively lower costs compared to optical fiber and coaxial cable.

STP cable was help produced by IBM, a multinational company. STP Cable has a metal foil or braided-mesh covering thant encases each pair of insulated conductors. The metal casing improves the quality of cable by preventing penetration of noise or crosstalk. This metal also cause the cable to be bulkier and more expensive.

Coaxial Cable

Coaxial cable or known as coax is a cable consisting of an inner conductor which is the central core conductor of solid or stranded wire. It is surrounded by a tubular insulating layer typically made from a flexible material with a high dielectric constant, all of which is then surrounded by another conductive layer, typically of fine woven wire for flexibility, or of a thin metallic foil. Finally it is covered again with a thin insulating layer on the outside. The whole cable is protected by a plastic cover which we always see. The term coaxial comes from the inner conductor and the outer shield sharing the same geometric axis. Coaxial cables are often used as a transmission line for radio frequency signals.

Coaxial cabling is mainly is used by the cable television industry and is also widely used for computer networks, such as Ethernet. It is quite expensive than standard telephone wire and it is much less susceptible to interference and can carry much more data.

My answer to Operating System

2011-05-14T07:58:00.000+08:00

Operating system is like the heart of the computer. It manages computer hardware as well as services for execution of application software. In simple thought operating system is a software program enables the computer hardware to communicate and operate with the computer software.
Operating systems perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as disk drives and printers.

Operating systems can be in five categories:

multi-user : Allows two or more users to run programs at the same time. Some operating systems permit hundreds or even thousands of concurrent users.
multiprocessing : Supports running a program on more than one CPU.
multitasking : Allows more than one program to run concurrently.
multithreading : Allows different parts of a single program to run concurrently.
real time: Responds to input instantly. General-purpose operating systems, such as DOS and UNIX, are not real-time.

Operating Systems provide a virtual machine to users that is more convenient to use. The structurally Operating Systems can be design as a monolithic system, a hierarchy of layers, a virtual machine system, an exokernel, or using the client-server model. The basic concepts of Operating Systems are processes, memory management, I/O management, the file systems, and security.

Research from:
http://www.computerhope.com/os.htm
http://www.personal.kent.edu/~rmuhamma/OpSystems/Myos/osIntro.htm
http://www.webopedia.com/TERM/O/operating_system.html
http://en.wikipedia.org/wiki/Operating_systemMy

Download Windows 7 Service Pack 1

2011-02-23T10:58:00.001+08:00

Windows 7 Service Pack 1 is Ready for Download

Microsoft has released its first Service Pack for the Windows 7 operating system addressing minor OS nips and tucks.

By Jared Newman, PCWorld Bug fixes and security patches don't make for the most exciting Windows update, but they're the high points of Windows 7 Service Pack 1, now widely available for download.

Windows 7 Service Pack 1 is now available from Microsoft's Website for download, or via Windows Update, and by ordering an installation DVD. Windows 7 SP1 takes roughly 30 minutes to install, and you'll have to restart the computer halfway through. System requirements and detailed installation instructions can also be found on Microsoft's Website.

Here are the most notable changes in SP1:

*A bug fix for HDMI audio devices that stopped working after restarting the computer

*Corrected behavior when printing mixed-orientation XPS documents

*Changed behavior of the "Restore previous folders at logon" functionality so that all folders are restored to their previous position, rather than in cascading order based on the most recently active folders.

The service pack also includes all previously released security, stability and performance updates for Windows 7. Like I said, not very exciting.

But there is one interesting nugget to note if you're an enterprise user: Microsoft is no longer saying that you'll need Service Pack 1 to install the final version of Internet Explorer 9, whenever it's released. If you don't have the service pack installed, IE9 will take the liberty of installing additional operating system components that are already part of SP1. With IE9's release candidate now available, that's good news for IT pros who may have been reluctant to upgrade in lieu of the service pack.

If you're going to update, Microsoft recommends backing up your computer to an external hard drive, DVD/CD or network location. Don't worry; Windows 7's built-in backup feature is actually decent.

Solve Staving Off System Failures with Automatic Defrag

2011-02-23T10:53:00.001+08:00

Automatic Defrag Solutions Key to Staving Off System Failures

By Beecher Tuttle; As any office worker can tell you, computer performance problems can be a major strain on productivity. Slow boot-times, random crashes and general operating issues can be extremely frustrating and costly for companies that rely heavily on computing technologies.

The majority of enterprises, SMBs and home offices spend thousands of dollars a year struggling to correct these issues because they assume that the problems originate in the operating system. In actuality, many computer issues are due to disk fragmentation.

Diskeeper, a leading provider of defrag solutions proven to reverse the effects of disk fragmentation and even eliminate its onset, recently published a list of 10 things that companies should know to keep their systems performing at the highest levels.

One of the critical facts that all computer owners should know is that disk fragmentation, which naturally occurs in most computers, has dire consequences. Fragmentation leads to slow data retrieval, which often results in delayed response times, crashes, data errors, file corruption and slow boot-times. Furthermore, servers are especially vulnerable to fragmentation, making defrag solutions critically important to today's businesses.

Another key fact is that the disk is naturally the slowest part of any system, making it imperative to keep it at top performance. With severe disk fragmentation, the entire system can be adversely affected.

While defrag solutions are quickly becoming a necessity for most businesses, Diskeeper warns that not all products offer the same defense against fragmentation.

Most defrag solutions don't pay extra attention to volumes where space is limited, which is where defragmentation is most necessary. Moreover, these cookie-cutter solutions do not distinguish files that are rarely used from those that are accessed on a daily basis, which are obviously more important. Diskeeper's auto defrag takes into account both of these issues, with no system resource conflicts.

To check out the entire list of facts, click here, or go to Diskeeper's website to learn more about the company's award-winning automatic defragmentation solution.

Google and Apple declared competing online payment systems

2011-02-22T10:37:00.000+08:00

Online Payment Systems

Google and Apple last week declared competing online payment systems to provide publishers to charge for content on digital devices. Apple's system is designed to work with the iPhone, iPad and iPod touch, while Google declared its will work with "tablets, smartphones and websites." Presumptively most of the tablets and phones will be running Google's Android operating system but it's possible that its system will also work on other mobile platforms.

One difference between the Apple and Google platforms is that Apple will charge publishers 30 percent of the subscription revenue while Google plans to keep only 10 percent. But perhaps more important distinction is the way the two companies plan to handle customer data.

Administrator Password

2008-10-31T18:35:00.004+08:00

How to log on using Administrator password?

Reboot your computer
When welcome screen is shown, hold CTRL+ALT and press Del

This info is very useful when you got the Administrator password, but not the Admin password. Maybe somebody change your Admin password?-smile-

Java Question

2008-09-06T14:51:00.006+08:00

Java Question

Write a program to show the following output:

ForLoop.java

public class Forloop{

public static void main(String[]arg){
System.out.println("This is by using for loop \n");
for (int i = 1; i<=9; i++) {
for (int j=1; j<=i; j++)
System.out.print(i);
System.out.println();
}}}

Modify the previous program to show the following output:

ForLoop.java

public class Forloop{

public static void main(String[]arg) {
System.out.println("This is by using for loop \n");
for (int i = 8; i>0; i--) {
for (int j=1; j<=i; j++)
System.out.print(i);
System.out.println();
}}}

Visual Basic .NET Question

2008-09-06T07:53:00.006+08:00

Visual Basic .NET Question

Write a command button event procedure that asks the user for the state and the country in two separate input boxes. Concatenate the names with a comma and space between them and display the merged state and country string in a message box.

Public Class Form1

Private Sub btn_Concatenate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs)Handles btn_Concatenate.Click

MessageBox.Show(txtState.Text & "," & " " & txtCountry.Text, " State & Country") 'Comment: State & Country is for your title

End Sub
End Class

Diploma in IT Question

2008-04-16T16:54:00.001+08:00

Diploma in IT Question

Question 1
List down common hardware resources managed by the Operating System

Answer 1

Processors
Memory
Input/Output Devices
Communication Devices

Question 2
Briefly explain Direct Memory Access(DMA)

Answer 2
Direct Memory Access(DMA) enable devices and controllers to transfer data to and from main memory directly. Furthermore, processor is free to execute software instructions.

Question 3
What is memory manager?

Answer 3
Memory manager strategically obtain optimal memory performance. It determine which process will stay in memory, where in memory each process will go and how much memory will each process have access to.

Question 4
Give four functions of a file system

Answer 4

Primarily are concerned with managing secondary storage space, particularly disk storage
Organize files and manages access to data
Responsible for file management, auxiliary storage management, file integrity mechanisms
Access methods

–

Microsoft Windows Server 2008

2008-03-11T17:34:00.001+08:00

Microsoft Windows Server 2008

Windows Server 2008 is the most recent release of Microsoft Windows's server line of operating system. It was released on February 27, 2008, becoming the successor to Windows Server 2003. Microsoft Windows Server 2008 was the showcased for the next generation of infrastructure and application platform products by the Microsoft Chief Executive Officer, Steve Ballmer.

The next generation of the Windows Server operating system is built-in Web and virtualization technologies, is designed to help increase the reliability and flexibility of server infrastructure . The new server Operating System, code named Longhorn, also built from the same code base as Windows Vista; therefore, shares much of the of Windows Vista and it also shares the same kernel with Windows Vista and incorporates many additions compared to its predecessor such as same architecture and functionality.

Define Operating System

2008-03-10T23:07:00.000+08:00

Define Operating System

An operating system known as OS is the software that manages the sharing of the resources of a computer and provides programmers with an interface used to access those resources. In other word, OS is a software program that enables the computer hardware to communicate and operate with the computer software. It is the most important program that runs on a computer.

An operating system processes system data and user input by recognizing input from the keyboard, sending output to the display screen, and responds by allocating and managing tasks such as keeping track of files and directories on the disk and internal system resources as a service to users and programs of the system. Furthermore, Operating systems controls peripheral devices such as disk drive and printers. OS also controls access to the system to provide security.

OS is the basic program of every computer and not all computers use the same operating system. Without an operating system, a computer could be useless. Some examples of GUIs operating systems are Linux and Windows.

Computer Trap Mechanism

2008-03-09T15:54:00.000+08:00

How the trap mechanism prevents a running program from tampering with the operation of the OS

Interrupt is called a trap. Interrupts enable software to respond to signals from hardware. It may be initiated by a running process of synchronous with the operation of the process. For example, dividing by zero or referencing protected memory may be initiated by some event that may or may not be related to the running process of asynchronous with the operation of the process. For example, a key is pressed on a keyboard or a mouse is moved.

Interrupts is a mechanism for quickly changing program environment. Interrupts transfer of program control is initiated by the occurrence of either an internal event or an event in its external hardware. The Interrupt-service routine a section of program to which control is passed when an interrupt signal occurs.

Interrupt processing has some basic requirements from the CPU. Before it can respond to an interrupt, the processor must wait for an "interruptible" state in its processing. For example, if the processor's writing to memory, it must wait until the write is done before processing the interrupt. Once the CPU detects the interrupt, its first action is to save all the information it will need to resume normal processing once the interrupt is over. At a minimum, the chip saves the Program Counter (PC). This process is analogous to you placing a finger in a book when someone interrupts you while you're reading. After the interruption goes away, you know exactly where to continue.

Software interrupt which is generated within a processor by executing an instruction. Implementing system calls requires a control transfer which involves some sort of architecture specific feature. Interrupts transfer control to the kernel so software simply needs to set up some register with the system call number they want and execute the software interrupt.

When the interrupt occurs, the processor also sends out an acknowledge signal analogous to the CPU memory read signal that other parts of the system use to place information onto the processor's data bus. Such multiple signals allow the processor to get additional information about the interrupt from the hardware.

A breakpoint interrupt is initiated by execution of the breakpoint instruction. The instruction can be inserted at strategic points in a program that is being debugged to cause execution to be stopped automatically. The service routine can stop execution of the main program, permit the programmer to examine the contents of registers and memory, and allow for the resumption of execution of the program down to the next breakpoint.

So, if an interrupt is generated inside the CPU, it is called a trap. A trap triggers the same hardware interrupt mechanism. It is also possible for two or more interrupts to occur at same time. When this happen, the CPU must honour the interrupt that is assigned with the highest priority which is for example, priority is given to the operation of OS if running program trying to tamper the OS operation.

The trap mechanism involves a set of service routines executed on behalf of user programs by the operating system. The trap mechanism instruction start when a user program wishes to have the operating system execute a specific routine on behalf of the user program, and then returned control to the user program, the user program uses the trap instruction. Then, a linkage back to the user program. The service routine must have a mechanism for returning control to the user program. This trap instruction causes the service to execute. It changes the PC to the starting address of the relevant service routine on the basis of its trap vector. Interrupt vector is where the interrupt handlers are stored in an array of pointers. It also provides a way to get back to the program that initiated the trap instruction. The “way back” is referred to as a linkage.

After the interrupt completes, the interrupted process is restored and executed or the next process is executed, if the OS wants to return to the program being interrupted, it does two things. First it restores the working registers of the program, and then it executes the iret(interrupt return).

Web Server Computer

2008-03-09T15:47:00.000+08:00

Class of Operating System which are appropriate for Computer Running a Web Server

A server operating system is intended, enabled, or better able to run server applications. The differences between the server version and the "workstation" version of an operating system vary. A server computer is a computer system that has been designated for running a specific server application or applications. A computer that is designated for only one server application is often named for that application. For example, when Apache HTTP Server (software) is a company's web server, the computer running it is also called the web server.

Batch System is the suitable classes of operating system for computer running a webserver. The popular operating systems for server is like as FreeBSD, Solaris, and Linux.
Server-oriented operating systems tend to have certain features in common that make them more suitable for the server environment, such as:

the absence of a GUI (or an optional GUI) which give the ability to be reconfigured (in both hardware and software) to at least some extent without stopping the system

· have advanced backup facilities to permit online backups of critical data at regular and frequent intervals and facilities to enable the movement of data between different volumes or devices in such a way that is transparent to the end user flexible and advanced networking capabilities

· features (such as daemons in UNIX or services in Windows) that make unattended execution of programs more reliable

· tight system security, with advanced user, resource, data, and memory protection.

Because the requirements of servers are, in some cases, almost diametrically opposed to those of single user-desktop computers, it is extremely difficult to design an operating system that handles both environments well, thus batch system is the most appropriate one.

Desktop Computer Single-User

2008-03-09T15:37:00.000+08:00

Class of Operating System which are appropriate for Single-User Desktop Computer

Single-user desktop computer is a system designed for only one user or single user/simple monitor. Also called a PC or personal computer. Single user is a mode in which a multiuser computer operating system boots into a single superuser(the term used for the special user account that is controlled by the system administrator). Some tasks may require exclusive access to shared resources, for example running fsck(file system consistency check) on a network share. This mode may also be used for security purposes. For example network services are not run, eliminating the possibility of outside interference.

A computer designed for use by a single user, with everything a user could need for basic computing, including the ability to process and store information. IBM introduced its first single-user computer as the IBM PC in 1981, and in the last 15 years, the term has come to represent any computer based on the IBM standard.
The other standard in the personal computer market is the Apple Macintosh. Software and peripherals specify whether they work on IBM-compatible PCs or Apple Macintosh platforms. In addition to standard abilities such as word processing, PCs have brought a wide variety of new possibilities to home users. Today a PC can be used to play high-tech video games, access huge amounts of information, and contact people around the world. The growth of the Internet and the World Wide Web has opened up a vast new world of opportunities for PC users.

Operating System Type

2008-03-09T14:57:00.000+08:00

Classes of Operating System which are appropriate for
Computer-Controlled Engine Management System

Real-time operating system (RTOS) is a multitasking operating system intended for real-time applications. Such applications include embedded systems (programmable thermostats, household appliance controllers, mobile telephones), industrial robots, spacecraft, industrial control (see SCADA), and scientific research equipment.

An RTOS facilitates the creation of a real-time system, but does not guarantee the final result will be real-time; this requires correct development of the software. An RTOS does not necessarily have high throughput; rather, an RTOS provides facilities which, if used properly, guarantee deadlines can be met generally (soft real-time) or deterministically (hard real-time).
An RTOS will typically use specialized scheduling algorithms in order to provide the real-time developer with the tools necessary to produce deterministic behavior in the final system.

An RTOS is valued more for how quickly and/or predictably it can respond to a particular event than for the given amount of work it can perform over time. Key factors in an RTOS are therefore a minimal interrupt latency and a minimal thread switching latency.

A real-time operating system is appropriate for a computer controlled engine management as real-time operating system require a task be performed within particular time frame and oftenly required in short time. For example an autopilot feature of an aircraft must constantly adjust speed, altitude and direction. And such actions cannot wait indefinitely even sometimes cannot wait at all.

An engine control unit (ECU) is an electronic control unit which controls various aspects of an internal combustion engine's operation. The simplest ECUs control only the quantity of fuel injected into each cylinder each engine cycle. More advanced ECUs found on most modern cars also control the ignition timing, variable valve timing (VVT), the level of boost maintained by the turbocharger (in turbocharged cars), and control other peripherals.

Modern ECUs use a microprocessor which can process the inputs from the engine sensors in real time.

An embedded system is a special-purpose computer system designed to perform one or a few dedicated functions, sometimes with real-time computing constraints. It is usually embedded as part of a complete device including hardware and mechanical parts. In contrast, a general-purpose computer, such as a personal computer, can do many different tasks depending on programming. Embedded systems have become very important today as they control many of the common devices we use.

Since the embedded system is dedicated to specific tasks, design engineers can optimize it, reducing the size and cost of the product, or increasing the reliability and performance. So, its also usually used in a computer-controlled engine management system as most of them are embedded through the machines.