Operating system

Day 1 1/7

OS

• OS is the system software which creates the platform for other software and applications.

  • Interface between user and hardware

  • Resource Allocator

  • Program Controller

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• System Software

• It is the type of computer program that is designed to run computer hardware and application.

• The OS is the is best known example of system software

• OS manage all other programs in computer.

• Some of Example of System Software

  • BIOS

  • Boot Program

  • Assembler

  • Device Driver

Finctions of OS

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• Command Interpreter One of the major functions of OS is commands.

• OS need to provide the interface to the user for the communcation with the computer.

• A Command Interpreter is a program which reads the instruction given by the user.

• Command Interpreter provides a user interface to hide hardware details of the system from the user making system more user friendly.

• Two common Method for interfacing

  • Command Line Interface(CLI)

  • Graphical User Interface(GUI)

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Day 2 2/7

Process Management

• Process is "Program in execution".

• It is a part of program which is under execution

• Program is passive entity

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• Stack

• The stack contain the temporary data such as methods/functions,parameters,return address and local variable.

• DAta

• The section contains the global and static variables

• Text

• This includes the current activaity represented by the value of program counter and contents of the processor's register.

• Heap

• This is dynamically allocated memory to process during its runtime this memory can be released once execution is completed

State of Process

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Context Switching

Types of Process

1. I/O Bound

2. CPU Bound

Schedulers in OS

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Long Term Schedular

Short Term Schedular

Medium Term Schedular

• Swap area

Linux Command

Day 3 3/7

Day 4 5/7

Process Scheduling