Collins Guide chapter 12
This section includes theoretical aspects of software such as word processors, spreadsheets, databases, CAD and the internet.
Interface software allows users to interact with a computer-based machine. This includes graphical operating system interfaces such as Windows, Apple OS and Linux and interface such as mobile phone systems. Other types of interface include the Command Line (CLI) and Menu styles.
The aim of interface software should be to make the facilities of the machine as easy to use as possible: intuitive and friendly. The miniaturisation and increasing power of computers helps to make this possible on devices as small as mobile phones.
Example email software includes: MS Outlook, Eudora, GMail, HotMail, Mozilla. Compose and send mail. Receive mail. Send and receive attachments. Send mail to many recipients at once. Reply. Carbon Copy. Address book, mailing lists.
Software for browsing the world wide web. Wikipedia
Whenever you use an application you are almost certain to want to save your work as a file so that you can preserve it for future reference and do some more work on it. In a GUI this is generally done through the 'File' menu where there are options such as 'Save As', 'Save' and 'Save For Web'. In many applications there is a choice of file formats, for example in a word processor there will be the default format (.doc) for the current version of the software, there will be older formats for previous versions of the software and there will be alternatives for rival or open source software such as '.rtf' (rich text format). The latter is useful as a way of moving a document from a specific format (such as Microsoft Word) to a different software environment such as MS Works or a Macintosh computer. Graphics programs have a wide range of file formats available such as JPG, PNG, GIF, TIF, BMP and so on.
When a file has been saved it can be opened for editing and saved again, possibly with a different name so that the original is preserved. An existing file can also be copied, for example to a backup device such as a memory stick or CD-ROM so that it can be preserved or moved to a different computer. Files are now commonly moved via the internet.
Computer devices are reliable these days but problems can arise. What do you do when a device such as a printer or a router does not work? Look in the manual - there is often a trouble-shooting page. Check the connections. Turn it off and on. Phone a help line (generally very expensive and a last resort).
There is an almost endless range and variety of software products to match the tasks that people want to carry out.
Tasks must be carefully defined before a solution in software can be created. For example, a flight simulator can be produced only when everything is known about the way an aircraft behaves when in flight; this becomes even more complicated when simulating the behaviour of a particular air craft. Similarly an air traffic control system can only be developed in software when everything about air traffic control is now and understood. All possible events must be built into software like an air traffic control system because it is 'mission critical'. If something is left out of a mission critical system (such as a nuclear power plant control system or a railway control system) then disaster may ensue.
Documentation is needed so that others may understand what programmers and application developers have done. User documentation is produced so that users can learn how to use software (many people ignore it and get by with a minimum understanding). Technical documentation is written so that other programmers can understand how the software was written and can develop it further (it would be very rare for the same programmer to work on the same piece of software over, say, 10 or 20 years; software teams change all the time so documentation is necessary for them to understand what is going on.
The requirements of a computer system are established at the start of a project. This would often be known as the 'requirements specification' and would come after 'requirements analysis'. The process of systems analysis involves investigating the needs of a user to check what they want a system to do. When the system is completed the final product can be compared with the initial specification to check that the requirements have been met. It is a fairly common occurrence, especially in government-sponsored projects, that requirements are not met within the time period allowed for the project. If requirements are too complex or change during the lifetime of the project then the software is unlikely to meet them, leading to arguments and legal action.