Transcript 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.
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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
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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
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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?
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Computing