1. Ajmer Singh PGT(IP) Software Concepts

2. Ajmer Singh PGT(IP) Operating System It is a program which acts as an interface between a user and hardware.

3. Ajmer Singh PGT(IP) Need of Operating System Operating system provides a software platform, on top of which, other programs, called application programs are run.

4. Ajmer Singh PGT(IP) Major Functions of an Operating System Communicate with hardware and the attached devices [Device Manager] Manage different types of memories [Memory Manager] Provide a user interface [Interface Manager] Provide a structure for accessing an application [Program Manager]

5. Ajmer Singh PGT(IP) Major Functions of an Operating System Communicate with hardware and the attached devices [Device Manager] Manage different types of memories [Memory Manager] Provide a user interface [Interface Manager] Provide a structure for accessing an application [Program Manager]

6. Ajmer Singh PGT(IP) Major Functions of an Operating System Enable users to manipulate programs and data [Task Manager] Manage the files, folders and directory systems on a computer [File Manager] Provide basic networking structure for LAN and Internet [Network Manager] A smart OS also provides a minimal security to the computer system through authorization (user name) and authentications (password) [Security manager]

7. Ajmer Singh PGT(IP) Types of Operating System  Single Program OS: In this, only one user program can be supported and executed at any time.  Multiprogram OS: In this, more than one user program can be supported and executed.  Time Sharing OS: In this, each active user program is given a fair share of CPU time, if the time elapses or an I/O operation is requested, CPU shifts over to the next program waiting and the previous program is put to wait.

8. Ajmer Singh PGT(IP) Types of Operating System  Real Time OS: In this, jobs have fixed deadlines and the jobs have to be completed within their deadlines.  Multiprocessing OS: It is capable of handling more than one processor.