ICT GCSE Revision

ICT systems require hardware, software, data and people. Data includes communications technology eg. the Internet.

There are three types of ICT systems: Information systems - manage data eg. supermarket stock system, Control systems - give instructions to machines and Communication systems - transport data between places eg. email.

What you get out of an ICT system is only as good as what you put in - GIGO (Garbage in, Garbage out). ICT systems work by receiving input in the form of instructions and data, processing it and producing output which gets stored or sent off somewhere. The higher the quality of the input, the better the output.

Feedback is where the output of a system is fed back into it to influence the input. Due to it being a repeating process, it is sometimes called a feedback loop.

There are 4 main phases: Analysis - studying the problems and coming up with solutions, Design - drawing up a specification for the new system, Implimentation - actually making the thing and finally Evaluation - making sure it all works.

A feasibility study is produced to show whether the project is technically possible and worth the cost of development.

A data flow diagram would be used to show the flow of data around the new system.

Every computer is made up of hardware, software and data. To evaluate whether hardware or software is suitable for a particular task, you need criteria to test against.

Hardware features can easily be compared by things like speed, processing power and RAM but for software, it's a bit more subtle. Here are some questions which should be asked in order to test the software suitability: Does it meet end user needs? What about functionality? How is its performance? Is it easy to use? Is it intuitive? How robust is it? Is it compatible with other pieces of software? Is it likely to crash? How expensive is it? Is there customer support available if required?

There are three main types of software: Bespoke - tailor made to do its job, Specialised - more specific uses eg. pay roll, company accounts and Generic - normal software used by individuals eg. word processing software.

Rigorous testing is needed as some software only breaks when it's stretched to its limits (a bit like an elastic band) eg. when releasing upgrades. An evaluation criteria is needed to decide which new hardware or software to purchase and how it will be used. Benchmark tests are used to assess the hardware or software.