GCSE ICT Revision, Hardware

Computer Definition- An electronic machine that processes data. It follows instructions given to it in the form of a program

PDA- A small hand-held computer that can be used as a PC, web browsing, mobile phone or media player, they're either touch screen or used with a stylus

Mainframe computers- Are large, expensive computers that support many users at the same time.

System- A collection of parts that work together for a particular purpose, e.g banking systems.

Dedicated computer- Are designed to work in just one particular situation

Embedded systems- Computer systems inside electronic devices to control them, e.g digital watch

Hardware- All the physical equipment you can see and touch

Central Processing Unit (CPU)- A set of very small electronic circuits that control the computer by running the programs, these programs are stored in RAM

Motherboards- All electronic components in a computer are attached to a plastic card called a motherboard

Memory- ROM and RAM

ROM- Read-Only Memory, contains basic instructions which stay there even when the computer is turned off

RAM- Random Access Memory, Stores data and computers need a lot of RAM.

Input devices- Are needed to put data into a computer 

Common examples- Keyboard, Mouse, Touch Pad, Webcam, Microphone, Scanners, Joystick, Touch Screen

Automated data input- Automating data input saves money and time with also a less risk of mistakes. Examples: OCR- Reads human readable letters, Used for: Number plate recognition    OMR- Reads pen marks, Used for: Lottery enteries or Exam papers. Bar Code Scanner- Reads the bars on products, Used for: Supermarket checkouts

Sensors- Detect events in the real world and produce electrical signals. Real-world energy is analogue meaning it varies continuously e.g temperature in a room. Computers need to read digital signals so the output from the sensors must be converted from analogue to digital signals using an analogue to digital convertor.

Computers process the data they are given as input and they then pass back results as output.

Printer output- Is called hard copy, and it can be used: To look at when there is no computer access, or, As proof that something took place

Common output devices- Laser printer, Ink jet printer, Speakers, Headphones, Touch screen

Specialist output devices- Plotter, Actuators, Lights (Traffic lights etc) Motors, Robot arms

Memory- The smallest