System Software

Why do we need an operating system?

• manges memory

• manages file

• handles external storage

Single User

Multi user

• gains access to facilities

• support the us of computers by many different users

• all user must have a number slection

• Must ensure that processor time is shared between each user.

Multiprocessing

• requires two or more processors

• different parts are different

• they are not responsible

• can work together on same tasks

Multitasking

• single user perform more than one application

• processor switches on application resource

• peripherals cannot be shared

Multi-threading

• done through effective sharing pf resources

• threads are processors

• one thread may be unable to perform a task

Why do we need utility programs?

Disk Defragmenter

• it will also do the same with free space

• merges files

• over time data may nit be stored

Data Compression Software

• reduces physical size

• cannot save storage space

• transmission time cannot be reduced

Archive Software

• removes date which is no longer in regular

• Data may not be require for historical purposes

• compression is not avaliable