OPERATING SYSTEM

is a set of programs that controls all the hardware and application programs that make up the computer system.

        The operating system (OS) makes the computer       hardware conveniently available to the user and also hides the  complexities of the computer operation.

   The operating system interprets commands issued by application software. 

TYPES OF OPERATING SYSTEM

•Simple Batch System

•Multiprogramming Batch System

•Multiprocessor System

•Distributed Operating System

•Realtime Operating System

Simple Batch System

In this type of system, there is no direct interaction between user and the computer.

The user has to submit a job (written on cards or tape) to a computer operator.

Then computer operator places a batch of several jobs on an input device.

 Multiprogramming Batch System

•In this the operating system, picks and begins to execute one job from memory. Once this job needs an I/O operation operating system switches to another job (CPU and OS always busy). Jobs in the memory are always less than the number of jobs on disk(Job Pool).

 Multiprocessor System

A multiprocessor system consists of several processors that share a common physical memory. Multiprocessor system provides higher computing power and speed. In multiprocessor system all processors operate under single operating system. Multiplicity of the processors and how they do act together are transparent to the others. 

Distributed Operating System

•he motivation behind developing distributed operating systems is the availability of powerful and inexpensive microprocessors and advances in communication technology.

Utility software 

•Utility software is system software designed to help analyze, configure, optimize or maintain a computer.

•A compiler is a computer program (or a set of programs) that transforms source code written in a programming language (the source language) into another computer language (the target language), with the latter often having a binary form known as object code.

•Interpreter is a computer program that directly executes, i.e. performs, instructions written in a programming or scripting language, without previously compiling them into a machine language program.

•Linker a program used with a compiler or assembler to provide links to the libraries needed for an executable program.

•Loader a machine or person that loads something.

FUNCTION OF OPERATING SYSTEM 

 

•There are Many Functions those are Performed by the Operating System. But the Main Goal of Operating System is to Provide the Interface between the user and the hardware.

Device Management: OS manages device communication via their respective drivers.

File Management: A file system is normally organized into directories for easy navigation and usage.

Memory Management :Memory management refers to management of Primary Memory or Main Memory

Processor Management:In multi-programming environment, OS decides which process gets the processor when and how much time.

DOD Operation

•DOS (Disk Operating System) is an operating system that runs from hard disk drive

•Disk operating system is also used to describe several very similar command line disk operating systems

 

 VITUALIZATION

 

•OS virtualization

–Create a platform that emulates a hardware platform and allow multiple instances of an OS to use that platform, as though they have full and exclusive access to the underlying hardware

WHY VITUALIZATION