#introductiontooperatingsystemnotes

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Operating System Services

There Are Many Services Provided By Operating System To The User And Programs. The Services May Differ From One Operating System To Another. The Following Are The Operating System Services That Are Provided To Make The Work More Convenient.

1. Program Execution

The Operating System Help To Load A Program Into Memory And Run It. Thus, The Execution Of A Program Can Be Done Easily With The Help Of Operating System.

2.I/O Operations

Each Running Program May Request For I/O Operation And For Efficiency And Protection The Users Cannot Control I/O Devices Directly And Thus The Operating System Must Provide Some Means To Do I/O Operations.

3.File System Manipulation

Files Are The Most Important Part Which Is Needed By Programs To Read And Write And Files May Also Created And Deleted By Names Or By The Programs.

4.Communications

Many Times One Process Need To Exchange Information With Another Process, This Exchange Of Information Can Take Place Between The Processes Executing. On The Same Computer Or The Exchange Of Information May Occur Between The Process Executing On The Different Computer Systems, Ties Together By A Computer Network. Communications May Be Implemented By The Technique Of Message Passing Or Shared Memory.

5.Error Detection

It Is Necessary That The Operating System Must Be Aware Of Possible Errors And Should Take The Appropriate Action To Ensure Correct And Consistent Computing.         Read the full article

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Introduction To Operating System Concepts

Introduction To Operating System Concepts - What Operating System Do? , Computer System Organisation, Operating System Operation, Definitions.

What Is an Operating System?

A Program (Or) A Software Which  Acts As An Intermediary Between A User Of A Computer And The Computer Hardware.

Operating System Goals

To Execute User Programs To Make Solving User Problems Easier To Make The Computer System Convenient To Use To Use The Computer Hardware And Resources In An Efficient Manner Operating System Is A Manager That Need To Use All The Resources To Perform Management Duties.

User View

Extended Machine That Lower Level Details

System View

Resource Allocator  

Definitions

Resource - Component Of A Limited Availability Necessary For Effective Operation Process - Active Program Dead Lock - A Situation In Which Two Or More Competing Actions Are Each Waiting For The Other To Furnish, And Thus Neither Ever Does. Buffer - Area Of Memory That Stores Data Cache - Area Of Fast Memory That Stores Copies Of Data what is the difference between cache and buffer? Buffer Is A Area Of Memory That Stores Data And Cache Is Area Of Fast Memory That Stores Copies Of Data. OS Kernel - Contains Basic Functions(one process active all the time) Everything Else Is Either A System Program(Ships With The Operating System) Or An Application Program. Interrupt - Change In Flow Of Execution, Operating Systems Are Interrupt Driven. Volatile Storage - Volatile Memory Is A Computer Storage That Only Maintains Its Data While The Device Is Powered, Most(Random Access Memory) Used For Primary Storage In Personal Computers Is Volatile Memory. Persistent/Non-Volatile Storage - Non- Volatile Storage Is A Type Of Computer Memory That Can Retrieve Stored Information Even After Having Been Power Cycled. In Contrast, Volatile Memory Needs Constant Power In Order To Retain Data.  

Computer System Organisation

One Or More CPU's Device Controllers Connect Through Common Bus Providing Access To Shared Memory.

Concurrent Execution Of CPU's And Device Competing For Memory Cycles I/O Devices And The CPU Can Execute Concurrently Each Device Controller Is In Charge Of A Particular Device Type Each Device Controller Has A Local Buffer CPU Moves Data From/To Main Memory To/From Local Buffers I/O Is From The Device To Local Buffer Of Controller Device Controller Informs CPU That It Has Finished Its Operation By Causing An Interrupt

COMMON FUNCTIONS OF INTERRUPTS

Interrupt Transfers Control To The Interrupt Service Routine Interrupt Architecture Must Save The Address The Interrupted Instruction A Trap Or Exception Is A Software Generated Interrupt Caused Either By An Error Or A User Request       Read the full article

[smartcherryposts]

Introduction To Operating System Concepts

Introduction To Operating System Concepts - What Operating System Do? , Computer System Organisation, Operating System Operation, Definitions.

What Is an Operating System?

A Program (Or) A Software Which  Acts As An Intermediary Between A User Of A Computer And The Computer Hardware.

Operating System Goals

To Execute User Programs To Make Solving User Problems Easier To Make The Computer System Convenient To Use To Use The Computer Hardware And Resources In An Efficient Manner Operating System Is A Manager That Need To Use All The Resources To Perform Management Duties.

User View

Extended Machine That Lower Level Details

System View

Resource Allocator  

Definitions

Resource - Component Of A Limited Availability Necessary For Effective Operation Process - Active Program Dead Lock - A Situation In Which Two Or More Competing Actions Are Each Waiting For The Other To Furnish, And Thus Neither Ever Does. Buffer - Area Of Memory That Stores Data Cache - Area Of Fast Memory That Stores Copies Of Data what is the difference between cache and buffer? Buffer Is A Area Of Memory That Stores Data And Cache Is Area Of Fast Memory That Stores Copies Of Data. OS Kernel - Contains Basic Functions(one process active all the time) Everything Else Is Either A System Program(Ships With The Operating System) Or An Application Program. Interrupt - Change In Flow Of Execution, Operating Systems Are Interrupt Driven. Volatile Storage - Volatile Memory Is A Computer Storage That Only Maintains Its Data While The Device Is Powered, Most(Random Access Memory) Used For Primary Storage In Personal Computers Is Volatile Memory. Persistent/Non-Volatile Storage - Non- Volatile Storage Is A Type Of Computer Memory That Can Retrieve Stored Information Even After Having Been Power Cycled. In Contrast, Volatile Memory Needs Constant Power In Order To Retain Data.  

Computer System Organisation

One Or More CPU's Device Controllers Connect Through Common Bus Providing Access To Shared Memory.

Concurrent Execution Of CPU's And Device Competing For Memory Cycles I/O Devices And The CPU Can Execute Concurrently Each Device Controller Is In Charge Of A Particular Device Type Each Device Controller Has A Local Buffer CPU Moves Data From/To Main Memory To/From Local Buffers I/O Is From The Device To Local Buffer Of Controller Device Controller Informs CPU That It Has Finished Its Operation By Causing An Interrupt

COMMON FUNCTIONS OF INTERRUPTS

Interrupt Transfers Control To The Interrupt Service Routine Interrupt Architecture Must Save The Address The Interrupted Instruction A Trap Or Exception Is A Software Generated Interrupt Caused Either By An Error Or A User Request       Read the full article