Expansion slots

These are empty connectors inside the PC for adding components. An IBM PC has 5 slots to add extra circuits. Two of these are filled by the disk-controller card (which controls the operations of the disk) and the video-display card (which controls the display screen or monitor). This leaves the user to install 3 other add-jons to his PC. This might include common boards or cards to control the printer or a modem to add extra RAM.

Interfaces

Also called port or connector, these are sockets outside the system unit for adding components. There are two types of port:

• Parallel port - several information signals are loaded and sent at once.

• Serial port - each electronic signal is loaded and sent one

at a time.

-For example, the connection mostly used to connect the printer

(parallel port) is similar to the usual modem connection (serial port).

Every time a computer is turned on, it does a self-diagnostic check. One by one it makes sure all its memory chips are functioning properly before it starts its work. This is referred to as booting a system or start-up of a computer.

\ COMPUTER LANGUAGE

A computer, as you know, is an electronic device and its brain consists of numerous switches which can be switched on or off. This means that the computer understands the language of two words -"on" and "off". In numeric terms, off = 0 and on = 1.

This system is called the binary system.

The first computers could be operated only by setting a long series of switches on or off. But, we do not speak in binary terms. So, computer languages were created to make computers easy to use.

A computer language is an interpreter which uses terms which both the user and the computer understand. The most commonly used languages are BASIC, COBOL, FORTRAN, C and ADA.

Software

Software is a recording of a list of commands that someone has written in a computer language. Software is written to suit one's

own specifications and requirements.

Now, the next time you work on the computer, you will probably understand this wonder machine and its inner mechanisms, and also how useful it is - be it for a game of chess or for shooting missiles.