Operating System

Operating system provides link between the user and the computer. It enables the user to have complete control over the computer system by commands through the keyboard or any other input device. The supervisor part of an operating system resides all the times in the memory (RAM) of the computer after the computer is turned on. An operating system performs the following tasks:

1. Controls basic Input and Output devices.

2. Allocates system resources.

3. Manages storage space

4. Supports application software

5. Maintains security

6. Detects equipment failure

This enables the user to achieve high efficiencies of which the processing systems are capable. Operating systems can be classified as:

1. Single User Operating System

2. Multi-User Operating System


Single User Operating System

Single user operating systems are used on individual systems or Personal Computers. These operating systems reside on disks and re called Disk Operating Systems (DOS). Some of the most widely used single user operating systems are :

1. MS-DOS

2. PCDOS

3. OS/2

4. Windows 95


Multi-User Operating System


Multi-User Operating Systems are used for data processing on lrge computer systems. They enhance the potential of computer systems with multiprogramming, multiprocessing and timesharing facilities making them suitable for large organizations. Some of the multi-user operating systems are:

1. UNIX / XENIX

2. MACOSX

3. Windows NT

4. Windows 2000 Server