Computer Basics An overview of computer hardware ICT Tools: Computer Basics.

Computer Basics

An overview of computer hardware

ICT Tools: Computer Basics

Types of Computers

Computers come in all shapes and sizes,from tiny PDAs (personal digital assistants) to PC (personal computer) towers.

Handheld (HPC)

Laptop

PDA

Tower

Workstation

Desktop


Computer Structure

The diagram below shows a simple structure for the operation of a computer. Data is obtained for processing by the computer and then the results of the processing are output from the system.

Input Output

Data Storage

Process


InputThere are a wide range of input devices. Some of these input devices make use of human touch, light, magnetism, sound and control sensors.


The Processor

The Central Processing Unit (CPU) can be considered the ‘brains’ of your computer. It consists of a single chip inside a computer that does most of the work. It takes the information from the input devices and instructions from memory, processes the information and then sends the result to storage or to an output device.

Processors inside a modern PC include Intel Pentium III and Intel Celeron.

The power of the processor is indicated by its operating speed measured in MegaHertz, (MHz).


Types of Memory

All computers have memory to store instructions and data. There are two main types of memory

• RAM (random access memory)This is a temporary storage for data. Typical RAM in a desktop PC may be 64 megabytes (MB). The RAM clears when your computer is switched off.

• ROM (read only memory)This is memory stored in a chip which is not lost when the power is turned off. On most PCs this memory is quite small. It contains the essential instructions for the computer to start.


Data StorageComputers need both long-term storage (e.g. saving a graph to be printed out at a later date) and short term storage (eg remembering subtotals in calculations).

Short term storageComputers use the RAM to store data temporarily while you work on it. Once you are happy with the job, you store it on the hard disk.

Long term storage Floppy disks, magnetic tape, etc can be used to offload confidential data from the hard disk.


Modem

This is a device that allows computers to transmit information to one another via an ordinary telephone line. A modem can be either internal or it can be an external device.


Parts of a PC

A PC is a small desktop computer, normally made up of three basic groups:

• a base unit – containing processor, memory and disc drives

• a keyboard with a mouse and a monitor

• peripherals – additional devices connected to the computer.


Parts of a PC


Inside a PC

If you were to remove the outer casing of your PC you could look around inside, and you would find:


Inside a PC

A peripheral includes such things as a monitor, mouse, keyboard, modem, scanner, digital camera, and printer. Many of these devices attach to a expansion card.

The power supply converts the electricity from the wall outlet into the correct voltage for the computer.

Hard drive This is entirely internal. It is a rectangle about the size of a medium paperback book.

Microprocessor: a small, integrated electronic circuit that can performs specific tasks. Microprocessors (or chips) are located in all parts of the hardware.


Behind a PC

External devices connect to the computer in the back. the arrangement of these is quite varied from machine to machine. Note that many of the connectors come in two types: male and female. The male has the pins while the female has the holes. In Activity 2, you will look at these connections in more detail.

Serial Male Serial Female


In this section

• you will become more familiar with the terms used by computer manufacturers when discussing computer specifications

• you can use this knowledge to will help you to choose the right system for your needs.


Computer Basics An overview of computer hardware ICT Tools: Computer Basics.

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