Functions of an operating

Functions of an operating system

1. user interface

   • possible for the user to issue comands
     • Operating systems need to provide a means of communicating with them.
     • The user interface is the way in which users interact with computer hardware.

2. Multi-tasking

   • Most systems commonly have several programs loaded into memory at the same time.
     • The operating system will also be running lots of background tasks just to manage the computer itself.
       • A processor can only execute one instruction at a time (assuming it only has one core).
         • The operating system has to mange all the programs running to make sure each one gets enough processor time.

3. security

   • Operating systems usually allow the authentication of users, i.e. they can be set up to check that users are who they say they are.
     • This normally involves users having user ids and password.
       • Operating systems also handle file privileges, these are right assigned to users and group.
         • Operating systems also handle file privileges, these are right assigned to users and group.

4. Peripheral Management

   • Peripherals are any computer hardware components that are not part of the CPU i.e. Input, Output or Storage devices.
     • A function of the operating system is to manage these devices.
       • The operating system may need to find / ask user to install suitable drivers for the device to work.
         • These drivers allows an operating system to communicate with the device.

5. Memory Management

   • When a program is running it must be in the computer’s main memory (RAM). The main memory has a finite size.
     • The operating system must manage where in memory the programs will go.
       • The operating system tracks where programs and data are at any time to make efficient use of the space in memory and to make sure nothing gets overwritten by something else.
         • As a program is finished it can be removed from memory and as as new ones are run they will be loaded into memory.