System Software #3 (Functions of an operating system- part 1)

Starter : Retrieval Practice

What are the two types of operating system user interface?

The two types of operating system user interface a Graphical User Interface and a Command Line Interface.

A graphical user interface can be WIMP based – what does this mean?

WIMP based means that a Graphical User Interface includes Windows, Icons, Menus and Pointers.

Explain why CLIs aren’t suitable for everyday users?

CLIs aren’t suitable for everyday users as they are text based, meaning that users need to know specific commands to complete tasks.

Give two advantages of GUIs?

1. Easy to use especially for a beginner. 2. You don’t have to learn complicated commands.

Give two advantages of CLIs?

1. CLIs can be much faster than GUIs if the user knows the commands. 2. CLIs use less CPU processing time compared to GUIs.

Today’s learning: Operating System : Functions (what do they do?)

A quick reminder of the types of operating system that are around, some of which you will have used:

•Android OS •Versions have nicknames such as Jelly Bean and Kit Kat

OS X (Apple MACs) •Versions have nicknames such as “Mountain Lion” and “Snow Leopard”

•iOS (iPhone/iPad)

•MS-DOS and Windows

•Google Chrome OS (based on Linux)


Despite the various operating systems, they perform similar functions. One of those functions was discussed in a previous blog; the function of providing us with a user interface. Remember a user interface, allows the user to interact with a computer system. ( ‘Graphical User Interface’ and a ‘Command Line Interface’.)

In this post (and the next post) , we will look at the other functions that are carried out by the operating system. Here is a useful video to help us look at the other functions.

Courtesy of craigndave

Lets summarise some of the operating system functions covered in the video…..

The function of multi-tasking

You may use your computer to do several tasks at the same time with different software: ​
homework, playing music, messaging friends…

There are many background ​processes running on the ​computer as well​.

They are taking it in turns to get processor time to execute instructions​. The OS must manage how the processes share the processor.

The function of memory management

To run a program, the computer must copy the program from storage into main memory (RAM).

The operating system keeps a record of where each program and its data are located​. It must not overwrite existing programs​.

The function of peripheral management

Peripheral devices are computer devices such as keyboards, mice and printers, that are attached to the computer system. They are described as ‘not an essential part of the system’ (essential are the memory and microprocessor), hence the term ‘peripheral’.

The operating system must manage:

  • Getting input and sending output
  • Copying files from disk to main memory
  • Copy data files back to secondary storage

The access speeds of peripherals are relatively slow. For example the operating system can send data much faster to a printer than a printer can print them. The computer sends the printer output to a print buffer, a special area of memory in either the computer or the printer, at full speed. From here, it is transmitted it to the printer, typically a page at a time. The print buffer may store a number of jobs waiting to be printed.

The above screenshot shows a print buffer in action. It shows the status of each job in the buffer, and whether it is printing or waiting its turn.

The function of managing device drivers

A device driver is a program that controls a peripheral device such as a printer, VDU, CD-ROM drive etc. Each device communicates with the OS via its ​own driver​. Many device drivers are built into the operating system but if you buy a brand new type of device, it will be supplied with a driver, which you will need to install​.

Questions based on today’s learning … have a go before you hit the drop down box for the answer!

Operating systems manage ‘multi- tasking’ this means ….

The user can have several programs open at once and have processes running in the background. The OS will have to decide how these programs and processes share the processor time.

Operating systems are responsible for ‘memory management ‘ this means ….

The operating system keeps a record of where each program and its data are located​. It must not overwrite existing programs​.

Operating systems are responsible for ‘ peripheral management ‘ this means …..

They communicate and control devices such as mice, keyboards, monitors and printers. This can include sending print jobs to the printer.

Device drivers are …

software programs that allow the operating system and peripheral devices to communicate.

Now take the quiz…..


Further Reading: