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Lord AvaLon Friday, May 29, 2009 11:39 PM

About Computers


Stands for Random access memory. Its purpose is to store the information and instructions that operate the computer's programs. Typically, programs are transferred from storage on a disk drive to RAM. Random-access memory is also known as volatile memory because the information within the computer chips is lost when power to the computer is turned off.

A more recent development is solid-state RAM. Unlike standard RAM, solid state RAM can contain information even if there is no power supply. Flash drives are removable storage devices that utilize solid-state RAM to store information for long periods of time. There are mainly two types of RAM i.e. Dynamic RAM ([B]DRAM[/B]) and Static RAM ([B]SRAM[/B]), comparatively DRAMs are slower and cumbersome than SRAM which are faster, expensive and can hold more information.

Random Access Memory could be considered as an array of boxes, where each box holds a single byte of information. A computer having one megabyte of memory can hold up to one million bytes or characters of information. The speed of RAM is measured in nanoseconds (ns). Lesser the nanoseconds, faster the speed of the computer.


is a basic unit of measurement of information storage in computer science. It is a unit of information built from bits, the smallest units of information used in computers. Bits have one of two absolute values, either 0 or 1. A byte is usually composed of 8 bits, although bytes composed of 16 bits are also used.

Bits and bytes are the basis for creating all meaningful information and programs on computers. For example, bits form bytes, which represent characters and can be combined to form words, sentences, paragraphs, and ultimately entire documents.


Is a pointing device used with personal computers that have a graphical user interface. A user typically operates a mouse with one hand in order to move a cursor over images or text on a computer screen. Clicking buttons on the mouse activates, opens, or moves icons or other graphical objects on the screen when they are displayed under the floating cursor. The basic features of a mouse are a casing with a flat bottom, designed to be gripped by one hand; one or more buttons on the top; a multidirectional detection device on the bottom; and a cable connecting the mouse to the computer. By moving the mouse on a surface, the user typically controls an on-screen cursor.


In a Graphical User interface, icons are small images displayed on the screen to represent an object which can be operated by a user. Icons allow the user to control certain computer actions without having to remember commands or type them at the keyboard. Icons are a significant factor to make the operating system friendlier and are easy to work without keeping in mind the long commands to access any file.


Are the set of instructions or more generally a collection of computer programs which tell the hardware how to work and perform different tasks on a computer system. At the lowest level software is in a form of an assembly language, a set of instructions in a machine-understandable form. At the highest level, software is in a form of high-level languages, which are compiled or interpreted into machine language code. They can be further enumerated by the type of work done by programs. The three basic types are

[B]Operating system (System Software):[/B] It controls the working of a computer system and perform essential tasks like Disk maintenance and managing screen etc.

[B]Programming Software:[/B] These are basically tools use to create, debug, maintain, or otherwise support other programs and applications.

[B]Application Software:[/B] It performs productive tasks for user such as word processing and database management etc.

[B]Control Unit:[/B]

Basically a control unit is a central part of machinery that controls its operations. In Computer science, a Control Unit is an internal part of the CPU which co-ordinates the input (hardware that is used for providing information to the computer) and output (hardware that is used for receiving information from computer) devices of a computer. The functions performed by the control unit vary by the internal architecture of the CPU.


Local area network; is a collection of computers interconnected to each other and can share data, application and resources. Most LANs are used to connect workstations and personal computers. In a LAN, each host means individual computer has its own CPU with which it runs programs but it also able to access data and devices anywhere on the LAN. Physical connection between LAN devices can be a coaxial cable, pairs of copper wires, or optical fiber and furthermore each network device maybe linked to Hub or switch. Wireless connections also can be made using infrared or radio-frequency transmissions. More over, LAN can be connected with external resources using routers, bridges or gateways.

LANs are distinguished from other network by three characteristics:

[B]1)[/B] Their size
[B]2)[/B] Their transmission technology and
[B]3)[/B] Their topology


A modem converts a computer's digital signals into the telephone's analog signals. The word modem comes from the two steps in this process: "modulation" and "demodulation". The Modem enables computers to communicate with each other across Telephone lines. It modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information. The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data. Modems operate in full or half duplex mode, depending on whether they send data together or one at a time.


It is the part of CPU where arthmetic and logic operations are performed. The arithmetic operations include addition, subtraction, multiplication and division while the logic operations compare numbers, letters and special characters such as AND/OR. ALU is considered as the fundamental building block of Central processing unit. The processesors inside modern CPU’s accomodates very powerful and complex ALU’s.


These are special, high-speed storage area within the Central processing unit. The data must be represented in a register before it can be processed e.g. if two numbers are to be multiplied, both numbers must be in registers, and the result is also placed in a register.

The number of registers that a CPU has and the size of each (number of bits) help determine the power and speed of a CPU i.e. 32-bit CPU is one in which each register is 32 bits wide. Therefore, each CPU instruction can manipulate 32 bits of data.

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