Download COMPUTER HARDWARE

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
Standard Grade
Foundation
Computing
OPERATING SYSTEM
(OS)
An OS is a program that controls how the computer
works e.g. Windows XP. It will
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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
Standard Grade
Foundation
Computing
DIRECTORY / FOLDER
An area
where files
are stored is
called a
directory or a
folder.
Each folder may contain other folders
or documents
Standard Grade
Foundation
Computing
TYPES OF SYSTEM
Interactive System
Allows 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.
Standard Grade
General
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
Standard Grade
General
Computing
OPERATING SYSTEMS
File Management
Deals with how files are stored on
backing storage – save and load
Memory Management
Controls where programs &
data are placed in main memory
Error Reporting
Computer tells the user about
any mistakes made.
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Credit
Computing
UTILITIES
Background Job
A job which runs in the
computer system as the
user interacts with
another program e.g. print
job.
Standard Grade
Device Drivers
A 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
Credit
Computing
Human Computer Interface
Command Driven
Enter command for computer to
follow e.g. a Visual Basic program
WIMP (G
raphical
U I )
ser
nterface
MENU
WINDOW
ICON
POINTERS
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Menu Driven
Select functions
from a menu
Credit
Computing
DATA ACCESS
Sequential Access
Data put into order then
stored on tape. It is read in
the same order that it was
Random/Direct Access
stored. Good as a backup
Data can be found straight
but slow data access.
away. Good for day to day use
as fast, direct access to data.
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Credit
Computing
HIERARCHICAL
FILING SYSTEM
Directories
and
Sub-directories
Main/Root Directory
&
Sub-directories
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Credit
Computing
And there is more….
Can you wait for the next exciting chapter?
Standard Grade
Computing