Standard Grade Computing

OPERATING SYSTEMS

CHAPTER 20

Standard Grade Computing

SYSTEM SOFTWARE

System software is a collection of programs which help the computer to work properly. It includes the

• Operating system• Filing system• Translator programs

Foundation

Standard Grade Computing

OPERATING SYSTEM (OS)

An OS is a program that controls how the computer works e.g. Windows XP. It will

• Check input devices e.g. keyboard• Send data to output devices e.g. printer• Control data flow to/from main memory• Manage the filing system• Control system security• Provide the HCI e.g. WIMP• Report any errors

Foundation

Standard Grade Computing

DIRECTORY / FOLDER

An area where files are stored is called a directory or a folder.

Each folder may contain other folders

or documents

Foundation

Standard Grade Computing

TYPES OF SYSTEMInteractive SystemAllows the user & computer to communicate. Computer responds directly to commands e.g. word processing, a computer game.

Real – time System A system which responds immediately to input e.g. online booking system.

General

Standard Grade Computing

TYPES of FILE

PROGRAM Contains the instructions of

how to do a tasks e.g. payroll program for a large company.

DATA Used by the program when it is running e.g. employee wage details – basic pay, overtime etc

General

Standard Grade Computing

OPERATING SYSTEMSFile ManagementDeals with how files are stored on backing storage – save and load

Credit

Memory Management

Controls where programs & data

are placed in main memory

Error ReportingComputer tells the user about any mistakes made.

Standard Grade Computing

Device DriversA program added on to

the OS which allows the computer to

communicate with that device e.g. scanner driver

allows computer to read data from the scanner

UTILITIESBackground JobA job which runs in the computer system as the user interacts with another program e.g. print job.

Credit

Standard Grade Computing

Human Computer InterfaceCommand DrivenEnter command for computer to follow e.g. a Visual Basic program

Menu DrivenSelect functions from a menu

WIMP (Graphical User Interface)WINDOW

ICON

MENU

POINTERS

Credit

Standard Grade Computing

DATA ACCESSSequential AccessData put into order then stored on tape. It is read in the same order that it was stored. Good as a backup but slow data access.

Random/Direct Access

Data can be found straight away.

Good for day to day use as fast, direct access to

data.

Credit

Standard Grade Computing

HIERARCHICALFILING SYSTEM

Credit

Main/Root Directory

&

Sub-directories

Directories

and

Sub-directories

Standard Grade Computing

And there is more….

Can you wait for the next exciting chapter?