Functions of the Operating System

Functions of the Operating System

All the computers that we use need an operating system. It may be a large mainframe computer running UNIX, a desktop PC running Windows XP, or a handheld computer running Palm OS. All these systems need an operating system to make sure all the programs run smoothly.

the operating system is a link between hardware and application software

The operating system is a collection of special pieces of software that help the computer to operate normally. The operating system has two main sets of functions:

  1. In some ways you can think of the operating system as a type of caretaker: making sure that data is saved in the right place; programs are loaded into memory properly; and that the computer's filing system is all kept in order.
  2. In other ways, though, the operating system acts like a translator: enabling the computer's hardware and software to talk to 'foreign' hardware such as printers, scanners and mice.
    It also allows the application software to 'talk' to the computer hardware.



This is the set of programs that is held in ROM and is run once the computer first starts (boots up). The Basic Input/Output Systems software in a desktop PC allow the computer chips to accept data from a keyboard and display text and numbers on a VDU. Without the BIOS the computer would be effectively deaf and dumb: unable to communicate. As extra input and output devices (peripherals) are added then extra bits of software (called drivers) need to be loaded so that the computer can accept data input or send data output.
For example, when you buy a new printer, you have to load some special software (the printer drivers) that enable the operating system to communicate with the new hardware.

System Resources

As the computer runs, and programs save data to temporary storage areas in RAM and then load other pieces of data from memory the operating system has to make sure that the data is stored in proper sized chunks in the right place so that it can be found again efficiently.
In the same way, data stored to floppy, CD-ROM or hard disk must be stored in such a way that it can be found again quickly with no mistakes in the storage or retrieval. The operating system offers both the user and the application programs the chance to save data as a file; rename a file; load a new file; and delete files.


Some operating systems have functions in them that allow them to communicate with other computers: sharing both data and programs. The operating systems need to make sure that different types of computers (such as desktops and mainframes) can understand each other when connected to the same network as well as computers and other types of hardware (such as printers, modems, etc).
The other main job of the networked operating system is to offer system security. This may be a simple case of including a password before the operating system will allow a user to access the computer. Although it may include special filters that allow only certain computers to talk to others. The networked operating system is also able to give rights to certain users and not to others.

Now answer these questions:

  1. What does the B in BIOS stand for ?
  2. What does the I in BIOS stand for ?
  3. What does the O in BIOS stand for ?
  4. What does the S in BIOS stand for ?
  5. What operating system would a mainframe normally use ?
  6. What operating system would a desktop PC normally use ?
  7. What operating system could a handheld computer normally use ?
  8. What facility would a networking operating system offer ?
  9. What are the bits of software that help peripherals to work properly ?
  10. Where does the operating system store data on a temporary basis ?

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