6.3.2 Explain the function of operating systems.
Teaching Note:
Students need to be aware that an operating system is a collection of programs that cover the following tasks: input/output (I/O) control, file maintenance, software/hardware interface, memory management, user interface, software execution control, security. Virutal memory must be included but knowledge of threashing and paging is not required. This extends 3.3.2.
Sample Question:
One of the functions of an operating system is file maintenance.
(a) State two functions of file maintenance. [2 marks]
JSR Notes:
And actually, in terms of satisfying the assessment statement, you can’t do much better than the above teaching note. You should really have an understanding of what each of those things is, but listing them off as above would be a really good start. Never-the-less, what follows is a bit more on each of them. But a really good point to make here is that the following list is straight out of the syllabus, so it’s as good or better than any arrangement/order of the same things in the textbook; looking at and understanding both ways of putting it would be best.
Input/Output (I/O) Control – There needs to be a software interface between all peripherals and the computer; so here we’re talking about management of communication between the computer and all sorts of peripherals, like mice, keyboards, and printers, to name a few.
File Maintenance – This is all of the stuff that you’ll learn in topic 7 that is required to keep things functioning properly. The File Allocation Table, in particular has to be managed and maintained so that files are able to be found – and not just user files, but files used by the computer itself.
Software/hardware interface – All applications have to be able to properly access the various hardware they need, to do what they do. As does the operating system itself, in fact.
Memory Management – All activities that are going on in the computer would take all of the RAM if they could, so something has to parcel out the memory in a fair, and efficient manner, prioritizing as it goes.
User Interface – This is the Finder/Windows Explorer etc. It allows the user to interact with the computer, and to set it up in an optimal way for his/her particular circumstances.
Software Execution Control – This is the management itself of what applications run, and when.
Security - Everything from firewalls to user accounts to permissions are all part of this most important category of tasks.
Virtual Memory Management – Virtual memory is the use of the hard drive as RAM memory; it’s obviously slower, but almost all applications do use virtual memory, though they continually swap in and out of RAM the most important information needed.