Information and Communication Technology
The IGCSE ICT specification gives four main areas in which computers may be used:
business, entertainment, education, communication.
This does not mean that questions cannot be set in other contexts, but it is unlikely. Examiners set questions to comply with the specification, it saves arguments later on about whether or not the question is fair.
The areas given mean that you should make yourself familiar with a range of ICT systems suitable for use in schools, businesses and at home. Try to look at both high end and low end systems. Not all ICT systems will require the latest and greatest equipment.
What a user wants from a computer system is not always what they need from a computer system, and rarely what they actually get. Most systems end up being a compromise.
When choosing an ICT system, some things to consider are:
Cost. If you have enough money you can get a system which is reliable, easy to use, and performs the required tasks very quickly.
And you can have it now, or at least within a reasonable time.
But, in most situations, it's just too expensive.
So the first thing you should do when evaluating a system, is look at the budget.
Reliability. Some ICT systems are used in situations where a failure would be dangerous, or expensive, or both.
e.g. if an aircraft's control system fails it could potentially cause the aircraft to crash.
On the other hand if your PC crashes while you are doing your homework, it's just annoying that you'll have to do some of the work again.
In situations where reliability is important, high quality devices should be chosen and there should be built in redundancy and fault tolerance. In the example of the aircraft, at least three computers run the control software in parallel so that a fault in one machine does not cause a problem.
Task performance. In many cases, this is simply a matter of matching processing power to software requirement. If you want a business system that will run the latest version of MS Office, you just need to ensure that the specification is better than the minimum requirement of the software.
For most ICT systems, there will be one or two particular components that determine how well it will perform. e.g. the graphics card for a gaming computer, the amount and speed of the Random Access Memory / RAM for a machine working on 3D modelling, the size and quality of the monitor for a public information system.
How soon you need it. This can often be considered in relation to cost. Computer technology moves on very quickly. If you are able to delay a purchase even for a short time, you may be able to get more for your money. Or get what you originally wanted for less.
Ease of use. An ICT system must be usable. Ideally it should be intuitive and not require any user training.
Some systems are designed in that way, e.g. electronic ticket machines and public information points. Many other systems require a small amount of training or assume that people have used something similar before. e.g. mobile phones and PC operating systems.
When looking at how easy it is to use a system you should consider who will use it and how much training they will need. Training usually costs money and probably has to come from the overall budget for the system.
The types of ICT systems that you may be asked to evaluate are likely to be ones used in education, the home, or a small business.
You need to have some knowledge of how some common components affect a system.
Processors. For many years processors were compared in terms of bits and clock speed. By 2005 there were 64 bit processors reaching speeds of around 4Ghz. After that the race for pure speed changed to one of getting processing power by having multi-
Some top end graphics cards have processors with 10 cores.
How well a system uses multi-
Memory / RAM. More is better, up to a point. Different operating systems allow you to use different amounts of RAM.
e.g. most 32 bit versions can only use 4Gb of memory, while 64 bit versions let you use 128Gb.
RAM also comes in different speeds, measured in Mhz or in data transfer rates. Faster is better, up to a point. If a new, faster RAM chip is developed, older systems may not be able to use the increased speed. In most cases having more RAM is better than having a smaller amount of faster RAM.
The hard drive. Hard drive capacity has grown larger every year and has now (2013) reached 4 Terabytes in size. Given that 2Tb drives cost well under £100 and smaller drives are being discontinued, there seems little reason to select a small drive instead.
More important is the drive's speed and reliability. And of these, reliability should be the main consideration, when a hard drive breaks it can be very difficult to recover it's contents.
External storage devices. CD and DVD drives, external hard drives, flash drives, and more. Will they be used for making back-
You will need to consider how much material you need to store and what sort of access you require.
Large amounts of data require large amounts of writing time, putting a few Gigabytes of video onto an external hard drive is likely to be much quicker than putting the same material onto a DVD. On the other hand, a DVD would be a lot cheaper.
The monitor. Monitor types are looked at on the Hardware and Software page. Having decided on the type, you should consider the size, the resolution, and the refresh rate.
The size may be constrained by where the monitor has to go. It is no use getting a 22 inch monitor if it has to fit into a 16 inch gap. Other than that, the monitor should be large enough for the user to use comfortably from their normal working position.
The resolution is how many pixels the monitor can display. Most monitors have several settings available and you should ensure that the one you select can display the amount of detail that you require. Higher resolution is not always better. e.g. If you are using a word processor on a 19 inch screen with a resolution of 1280 x 1024 you will give a good picture, but on a 14 inch screen the text would be tiny and difficult to work with.
Refresh rate. This refers to how many times the picture is displayed every second and is determined by a combination of the monitor and the graphics card. Too low a refresh rate makes the monitor flicker. Different people can see flicker at different rates. 60Hz is usually regarded as being acceptable.
Higher refresh rates only become important if the monitor is going to be used for 3D display. Some graphics cards are able to supply 3D images if the user wears special shutter glasses. There are also passive 3D monitors available that use polarised glasses. In both methods, each eye sees a different picture so a rate of 120Hz is needed to show 60 pictures per second to each eye.
Printers. Printer types are looked at on the Hardware and Software page. The thing to consider is cost per print. Speed and quality are also important but these tend to be looked at in terms of cost. Faster printers cost more, higher quality print costs more.
If the printer is going to have to produce thousands of pages of print, laser printing is probably the best bet. If it just needs to produce the occasional letter, look at inkjets.
Then think about:
Every situation is different and systems must be designed to fit.
In the early days of computing, an Operating system / OS allowed you to control the computer and not much else.
Useful things like back-
Application software was also added on, but it differed from utilities in that applications were what you worked with to produce something, while utilities were things that helped keep your computer running.
Nowadays, the three software types have blurred. Most modern OSs come bundled with numerous utilities. When a 'full install' of the OS is performed, all the utilities are included e.g. firewall, anti-
The OS may also include simple applications such as a basic word processor.
Because of this blurring, the 4IT0 specification only uses two categories, system software and applications.
System software includes the OS and utilities. Application software is word processors, spreadsheets, etc.
There is still some overlap, but it is simpler than trying to work out if something is a utility or a part of the OS.
Choosing an Operating System. There are three main operating systems to choose from. MS Windows, Mac OS X, and GNU/LINUX. There are many other operating systems available but none of them have widespread support by manufacturers of home and office software.
You may be constrained to use a particular operating system because of what you already have. e.g. If all your present software is MS Windows based, it may cause too many problems if you change to LINUX.
If you are starting with a new system however, your choice may be based on what you need it to do. This is likely to be decided by three factors, cost, available applications, and what the user is used to.
Applications software. Here there is a choice of Freeware, Shareware, Open Source or Commercial software.
Freeware is software that is given away by it's author. Most Freeware programs are relatively simple applications that perform a single or small group of functions. e.g. a backup utility or a video converter. Some can be much larger. e.g. games such as OpenTTD or Widelands, Office suites such as Libre Office, or creative packages such as Blender.
Freeware may also be cut down or limited versions of commercial software, released in the hope that people will like it and purchase the full version. This is often known as feature limited or crippleware.
Freeware may be Open Source (see below) but does not have to be.
Open Source is free software that has had it's source code released. This means that people other than the original author can make changes to it. Open source is frequently used to develop substantial applications. e.g. Open Office is an open source office suite which mimics most of the functions of MS Office, and The Gimp is an open source art package.
Commercial is software that is sold or licensed.
The type of application software used in a system depends on what the user wants to be able to do, and on the money available. Until quite recently, freeware and open source software was regarded as being inferior to commercial software, but the success of LINUX, Open Office and other high quality products is changing that idea. Large companies and even national governments are now looking to cut costs by using open source.
When a system is being set up for a user or group of users, the system settings must be thought about.
Some users will be able to change settings for themselves, others will not know how to or might be prevented from doing so by company policy.
In situations where users are required to use fixed settings, it is important that those settings let the user do their job effectively.
Some user environment settings that should be considered are:
Mouse controls. Most mice have two buttons plus a scroll wheel. Some have more.
The mouse or operating system software can be used to set the functions of the wheel and buttons.
Mouse sensitivity may also be set, allowing greater or lesser movement of the screen cursor for a given movement of the mouse.
The screen cursor may be altered and a cursor trail may be enabled. Both of these changes might be useful the visually impaired or for situations where the screen is not clearly visible.
Icons. Icon properties such as size and colour may be changed using the operating system or a utility program.
Icons could be set to flash or change colour to indicate the state of the program that they represent. e.g. a print icon may flash red if the printer is out of paper.
Screen resolution. The maximum resolution that a screen will support is not always the best resolution to use. Resolution must be balanced against readability of the display.
Colours and contrast. These often go together. The colour scheme used and the contrast between the light and dark colours should be chosen to enhance the readability of the screen. Care should be taken with combinations such as red and green, which might cause problems for colour blind people.