1.Process management

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process: a prog in executation eg: a word processing program, sending o/p to a printer etc.

a program is a passive entity a process is an active entity

• functions assosiated with process management

  • Scheduling process and threads on the CPU (since there will be more than one process running)

  • Creating and deleting both user and sustem processes

  • suspending and resuming processes

  • providing mechanisms for synchronization

  • Providing mechanisms for process communicatino

all these are done through system calls

2.Memory management

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Mani memory is a large array of bytes ther arises the needfor memory management Instructions must be in memory fo rexections

• Functions associated with memory management

  • allocation and deallocation of memory space

  • keep track of which parts of memory are currently being used and who is using them

  • deciding which data to move in and out

3. Storage management

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1.file amanagement

• when multiple users tyr to access file, OS will control which user may access a file and how that user may access (eg: read, write, appedn)

• Functions associated with file management

  • creating and deleing derectories to organize files

  • Supporting primitives for manipulating files and directories

  • Mapping files into secondary storage

  • Creating and deletin file backing up files on stable storage media

2.Mass storage maangement

the computere system provides secondary storage to back up main memory

• Function with secondary storage management

  • Free-space management

  • Storage allcoation

  • Disk scheduling

• FUctions with tertiary manaagement

  • Mounting and unmounting media in devices

  • Allocations and freeing the devices for exclusive use by process

  • Migrations data from secondary to tertiary storage

3. Catching

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used for fast retrival of data

when updationn occurs in any part f the memory evry part should be updated ,its called cache coherency

spoolig : temperary data storage mechanism, stored in secondary storage devices

buffering : usees area inside the main memory

4.I/O systems

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act as an interface b/w user and system

• a general device-friver interface

• driivers for specific hardware devices

• a memory -management component htat includes buffering, caching, and spooling (*spooling taking space from the disk,used with data transfer b/w input output devices *buffering does not have a huge maount space, )

5.Protection and security

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• Mechanism for controlling the access of processes or users to the resources deefined b a comp system

• an unprotected resource cannot defend against use by an unauthorized or incompetent user

• A protection-oriented system provides a means to distinguish b/w authorized and unauthorized usage