o Controllingperipheral devices such as disk drivesand printers.

Generally, there are four types,based on the type of computerthey control and the sort ofapplications they support.1. Single-user, singletask This type manages thecomputer so that one usercan effectively do onething at a time.

2. Multi-user, multi-task

Allows two or more users to runprograms at the same time. Someoperating systems permit hundreds oreven thousands of concurrent users.

3. Real Time Operating Systems

RTOS are used to control machinery,scientific instruments, and industrialsystems.There is typically very little userinterfacecapability.Resources are managed so that aparticular operation executesprecisely the same every time.

4. Single-user, Multi-tasking

This is the type of operating system mostdesktops and laptops use today.\Microsoft’s Windows and Apple’s MacOS areboth examples of operating systems that willlet a single user have several programs inoperation at the same time.

Operating systems providea software platform on topof which other “application”programs can run.

•The application programsmust be written to run on aparticular operating system.

•So, your choice of operatingsystem determines whatapplication software you canrun.

• Besides managinghardware and softwareresources on the system,the OS must manageresources and memory.