What is software?
Software is the general name given to all the programs that can be run on computer hardware. There are two main categories of software: operating systems (systems software) and applications software.
Operating systems (systems software):
An operating system is a program that controls the hardware directly. Operating systems perform the following tasks:
They provide a way for applications software to communicate with the hardware. For example, in your word-processing package, if you click on the printer icon, the operating system gives an instruction to the printer to start printing.
They manage the system resources such as memory and allocate CPU time to the task being run.
They manage the transfer of data to and from the various peripherals (keyboards, mice, scanners, printers, etc.)
They manage system security. Many operating systems allocate certain rights to users. A user can only do certain things on entering a password.
Examples of operating system include Windows ME, Windows 2000, Windows NT, UNIX and OS/2.
The operating system provides an interface between the user and the computer hardware. Figure 5.1 helps to explain this. Without on operating systems, a computer would be useless, so the first thing a computer looks for when it is swished on is the operating system. Once the operating system has been found, the computer loads it from disk.
Multitasking means the ability of a computer to run two or more programs at the same time. As a user it may be hard to see how you can do two things at once. One way would be to print out a large document (say 20 pages) whilst continuing to use the word-processor to type in a new letter. The operating system takes care of the printing and the word-processing at the same time.
Other examples could include...