Architecture, Goals & Structures of O.S, Basic functions, Interaction of O. S. & hardware architecture, System calls,

Operating Systems 

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Q.        What is an operating systems ?       ---- 4 marks.

Definition of an OS
An operating system is an interface between users and hardware of a compute system. An operating system manages resources of a computer .

            These resources include :

a) Memory    b) Processor    c) Input / Output devices      d) File system

OS keeps track of each resource and decides who will get control over resources, for how long.

Architecture of an OS

                                                                                                      Fig . Architecture of an OS

Operating system makes computer more convenient to use. All resource are used in very efficient way.

Functions of an OS

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Q.        Explain functions of an operating system.   ---- 4 marks

Ans:-   Operating system works as an interface between user and the computer.

Functions of Operating System :-

1) Program Development :- Operating system provide a set of utility program which are necessary to program development. (e.g . Editor, linker, etc )

2) Program Execution :- Operating system handles loading of programs from secondary memory to primary memory. It makes program available for execution.

3) I/O Operations :- A running program may require I/O. I/O operations are handled by operating system.

4) File System Manipulations :- An operating system provides various system calls for manipulation of files.

5)  Communication :- Under many situations a process has to communicate with other process. Communication is required for exchange of information. Communication done through message pipes, mailbox, etc.

6) Resource Sharing and Protection :- Resources are shared properly with all processes as well as protection is also provided.

7) Error Detection :- Different types of errors may occur while a computer system is running.

8) Accounting :- Operating system keeps track of every action. For how much duration user has a log, what modifications he did , etc.

System Calls

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Q. Explain system calls and its different types ? ------ 4 marks

Ans:- System calls :-System calls provide interface between user program or application program and the operating system.

Types of System Calls :-

a) File management :- These system calls are used to create file, open file, close file, read as well as write files, etc.

b) Process Management :- System calls for process management are create, terminate, load as well as execute process.

c) Inter process communication :- For sharing information some system calls are used. It uses pipes, semaphore, mail box, message queue, etc for inter process communication.

d) I/O device management :- System calls for device management are request ( ) device, release  ( ) device.

e) Information processing and maintenance :- System calls for this category is set time, set date , get time, get date.

References

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  • Notes by Prof. D. B. Pawar, Team WikiNote, Pune
  • WikiNote Foundation

Last modified: Friday, 20 September 2019, 1:03 AM