what is microcomputer

what is microcomputer

A computer is an electronic machine that stores, retrieves and manipulates or processes data.

Microcomputers are microprocessor based small computer. The brain of a microcomputer is the microprocessor, a silicon chip containing the necessary circuits to perform arithmetic and logic operations and to control input-output operations. A microprocessor is an integrated circuit consisting of thousands of transistors squeezed onto a tiny chip of silicon. The chip is packaged as a single integrated circuit. Adding input-output capability and a memory to the microprocessor, a microcomputer system is formed.

Early microcomputers had a limited processing potential and limited choice of input-output devices. Present day microcomputers have wider processing capabilities and support a wide range of input-output devices. In addition to general-purpose computations, microcomputers are used for special purpose applications in automobiles, airplanes, toys, clocks, appliances etc.

High-end super micros are known as workstations. The workstation represents the bridge between the microcomputers and minicomputers. It is a microcomputer with many of the capabilities of larger minicomputers hut costing much less. Initially designed for use by engineers and designers, and today they are popular for general uses. These workstations can run more than one application for a user. This is known as multitasking. A workstation is also a multi-user system that can be shared by several users at the same time.

Different Types of Microcomputers
Today most of the microcomputers are IBM compatible. The microcomputers compatible with the line of IBM personal computers are known as IBM compatible computers. Compatibility here means that, components (hardware and software) of one ‘IBM computer’ is normally installable in another ‘IBM compatible computer’ and vice-versa. All IBM compatible computers have same line of microprocessor, input-output device, software etc. So it is possible to use one component of a computer in a compatible of that computer.

Different series of IBM compatible computers exist. They are:

•  IBM PC
•  IBM PC/AT
•  IBM PC/XT
•  IBM PS/2.

IBM PC
IBM PC was introduced in 1981. It has following characteristics:

•  Intel 8088 processor
•  16 KB RAM expandable up to 64 KB
•  Monochrome video adapter, incapable of displaying bit-mapped graphics
•  Floppy disk drive with 160 KB storage capability
•  No hard disk.

‘PC’ is the name of a compatible series of microcomputers. But this name ‘PC’ is also used to refer any microcomputer, where PC means personal computer. In this book where we used the term ‘PC’, it means any microcomputer except in this section.

IBM PC/XT
IBM PC/XT was introduced in 1983. It has following characteristics:

• Intel 8088 processor
• RAM expandable up to 640 KB
• Supports hard disk.

IBM PC/AT
IBM PC/AT was introduced in 1984. It has following characteristics:

• Intel 80286 processor
• It is approximately 75% faster than PC/XT
• AT bus standard was used in many clones.

‘Bus standard’ means the industry standard of connection point and connection organization of different devices connected with the motherboard.

‘Clone’ means a copy of the original one. In computer literature, it means compatibility. For example, ‘AT clone’ means a computer compatible to the IBM PC/AT series.

IBM PS/2
It was introduced in 1987. Different types of Intel processors are used here. It uses MCA (Micro Channel Architecture) bus standard.


Basic Parts of the Microcomputer:

Components Inside the Casing Inside the casing there are a few components:

•  Motherboard: Contains the circuit to combine different portions of a microcomputer.
•  CPU: It is the central device. It controls the whole computer through the motherboard.
•  RAM: It is the Random Access Memory. The CPU stores and retrieves data in RAM
•  ROM: It is the Read Only Memory. It contains the program that is run during the startup period. It also contains basic routines to control different I/O devices.
•  Bus slots: Different external cards are connected with the motherboard through the bus slots.
•  Memory card: Random Access Memory available in cards.
•  Display card: Controls the display unit.
•  Multifunction board: It contains
•  Printer port: Printer is connected through this port
•  System clock/calendar: Stores information about current date and time
•  Serial port (RS-232C port): Mouse, modem etc. are connected through this port.
•  Disk controller: It controls the floppy and hard disk.
•  Power supply unit: Supplies Power to the Microcomputer.
•  Disk drives:
•  Floppy disk drive: Runs floppy disk.
•  Hard disk drive: It contains the hard disk.
•  CD drive: Used to run the CD (Compact Disk)s .

Components Outside the Casing
The following components are connected externally with the casing.

•  Keyboard: Gets input from the user by key pressing.
•  Monitor: Displays the output
•  Mouse: Is used to point and select different elements displayed by the monitor.
•  Printer: Used to get the output in printed form.
•  Modem: Connects the computer with the telephone line.

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