Hardware and Software
A computer system is generally considered to be made of two parts—the hardware and the software. The hardware consists of the physical parts of the machine. The software consists of the information and the instructions given to the computer that enables it to operate. The information is called data and the set of instructions is called program.
Programming is the name given to the ‘art’ of writing a program. Every machine, depending upon its internal hardware architecture, has a unique low-level language called the machine language. In a binary-coded digital computer, the machine language is made up of Os and Is. Assembly Language uses mnemonics for machine language. To relieve the programmer from the agony of writing a program in the difficult low- level machine language, several hundreds of easier, high-level programming languages have been developed. High-level languages are comprehensible representations of machine code using mnemonics in Assembly Language.
Languages: Computer programming languages are often distinguished as being either compiled or interpreted languages. The user’s program in (the high-level programming language is called the source code. The manufacturer of the Computer supplies the required software, either a compiler or interpreter, for every user language implemented on it. The compiler translates the source code into a machine language program called the object code.
Today computers can be classified as Mainframe Computers, Minicomputers and Microcomputers. Mainframe Computers are expensive and large with centralised computing facilities where a Super Computer or a large computer is connected to several terminals. A multiuser mainframe computer has a large memory and is capable of speeds of the order of several millions of floating-point operations per second. Minicomputers are also multi-user computers having lesser memory and operate at slower speeds.
Microcomputers are often called Personal Computers or PCs since they were originally intended to be single user devices either at the office or at home.
The fourth generation microcomputer like the 1BM-PC is a small desktop system with two floppy disk drives. It employs a microprocessor and has a RAM, five expansion slots and functions under the Operating System called MS-DOS.
The Floppy Disk: The most widely accepted forms of auxiliary storage used in microcomputers is the floppy disk storage. A floppy diskette is around vinyl disk enclosed within a plastic cover.
Hard Disk: The Winchester or hard disk drives can store much more data than what can be stored on a floppy diskette. Hard disks come sealed and they cannot be removed or changed like floppy diskettes.
The Operating System
The Operating System of a computer is a group of programs that manages or oversees all the operations of the computer such as CPU, Memory, Keyboard, Floppy Diskette, VDU etc. The operating system is responsible primarily for managing the files on the disk and the communication between the computer and its peripherals. When power is supplied to the microcomputer, the operating system is first loaded (before the user program is entered) and this process is called booting.
Commands: All operating systems have inbuilt commands and small programs residing on disk which, when run, behave like commaPrinter:
The Printer: The Printer usually used along with a microcomputer is a dot matrix printer, wherein a!) pin (vertical) head creates matrix pattern to form the characters. However, nowadays, laser printers are more in vogue. A Laser (LASER : Light Amplification by Stimulated Emission of Radiation) is a device that harnesses light to produce an intense beam of radiation of a very pure and single colour.