COMPONENTS OF A COMPUTER

There many components of a computer let us know from the basics

COMPUTER HARDWARE

Computer hardware consists of input devices, output devices, circuitry, memory, and the central processing unit (CPU) where processing and operations are performed. Input devices, such as a keyboard or mouse, are the means by which the computer takes in symbolic data and instructions. Output devices, such as the monitor or printer, are the means by which the computer sends out the symbolic results.

The CPU is the brain that controls the rest of the hardware. It is made up of three different parts: the processor, arithmetic logic unit (ALU) and internal memory. The processing unit or processor controls all the other parts of the computer. It accepts input and stores it in the memory and it interprets the instructions in a computer program. The arithmetic logic unit (ALU) performs various operations, such as addition, subtraction, multiplication, division, as well as others. The processor and the ALU use a small amount of the internal memory; most data are stored in external memory devices using hard or floppy disk drives that are attached to the processor.

COMPUTER SOFTWARE

Computer software is defined as the programs that control the computer system. Software includes the operating system, system utilities, computer languages, and computer applications.

Computer design is based on devices with two states (open or closed circuits, on or off switches). The storage cells in the main memory are groups of electronic circuits, each of which is turned on (current flowing through it) or turned off (no current flowing through it). All the data and instructions stored in the computer are represented by strings of these "on" and "off" switches. Machine language is the language understood by the computer and is closely tied to the design of the computer. A bit, the smallest unit of storage in a computer, represents each "on" or "off" circuit. The smallest group of bits commonly addressed by present day CPU's is made up of eight bits, and is referred to as a byte. Because of this two state technology, machine language is written using two symbols, usually the digits 0 and 1. Therefore, machine language is also referred to as a binary language.

These strings of binary digits are very difficult for a human to decipher so a more compact form has been devised in which each group of three binary digits was replaced by a single number in the range 0-7 (octal digits). Machine language, which is a low-level language, may be different for various types of computers. Thus, the binary (base 2) sequence 010100011 010 000 010111 would be replaced by the octal (base 8) sequence 243 2 0 27.

A further development is the use of names to identify memory locations. These assembly languages use terms such as ADD (instead of the binary code 1101) and MOVE.L (A3),D0 (instead of the binary code 0010000000010011). An assembler translates the assembly language program into the machine language. But the language is still difficult and because it is specific to particular computers, the same assembly language program can not be run on different types of computers.

Computer software also includes software tools (editors, word processors, spreadsheet programs, and database management programs) and operating systems. An operating system is a set of programs that control the operation of the hardware of a computer and application programs submitted by users.