2. OPERATING SYSTEM
By
Syed Abdul Ghafoor Shah
Senior Subject Specialist
Govt. College for Elementary Teachers (M) Bahawalpur
3. What is
OPERATING SYSTEM
A Collection of system programs that controls and
coordinates the overall operation of a computer system.
Examples:-Microsoft windows, Linux, Unix, Sun
Solaris, Mac OS
4. FUNCTIONS OF OS
Acts as interface between the
hardware, application programs, files
and user.
A communication link between the user
and computer
Helps the user to run the application
programs
Manages the computer resources
(CPU, Memory and I/O devices)
6. LOCATION OF
OPERATING SYSTEM
A small part of operating system called
“Kernel” resides in memory(Main
Memory). It works in booting. Other
large part of operating system is stored
in secondary memory. It is swapped in
or out when needed.
10. SUPERVISOR
Major part of operating system that
controls the operation of the computer
Memory Resident
Supervises the loading of other part of
the operating system from Sec. to
Main memory
Loads programs or data into main
memory from backing storage
Scheduling the sequence of jobs to be
run
12. INTERRUPT HANDLER
Keeps track of all the process and
executions of commands
Displays error massages
e.g. not reading drive A
13. INPUT OUTPUT CONTROL
SYSTEM (IOCS)
Monitors the operation of input/output
devices
Controls and coordinates the flow of
data between I/O devices
18. STAND ALONE
OPERATING SYSTEM
That works on a desktop or notebook
Computer
When it works with a Network operating
system is called Client Operating system
Examples:-DOS, Windows XP, Windows
Vista, Macintosh OS
19. NETWORK OPERATING
SYSTEM
An OS that supports network
Allows to share resources such as hard
disk, printer etc.
Works on network server
Examples:-Windows NT Server, Windows
2003 Server, Netware, UNIX, Linux, Solaris
20. EMBEDDED OPERATING
SYSTEM
It is used in hand held devices
It resides on a ROM chip
Examples:- Windows CE, Windows
Mobile 2003, Palm OS
22. SINGLE USER
This OS can run only one program at
a time
Only one user is in command at any
given time
It runs on microcomputers
Examples:- DOS, Macintosh system
23. MULTI USER
Able to run several jobs at a time
Many users can use simultaneously
Run in main frames
Examples:- UNIX, ZNIX
24. FUNCTIONS OF
OPERATING SYSTEM
Memory management
Booting
Loading and execution
Disk management
Job scheduling
Device controlling
Accessing the Web
Providing interface
(Command line user interface/Graphical user
interface)
26. CLASSIFICATION OF OPERATING
SYSTEM
OR PROCESSING METHODS
Batch Processing
Online processing
Real time processing
Multiprogramming
Multiprocessing
Time sharing
27. BATCH PROCESSING
Also known as sequential
serial, Stacked processing or queued
processing
I. Jobs of different users are stacked in
queue
II. A batch of jobs when completed
is sent to processor
It is low cost but time consuming
28. ONLINE PROCESSING
A job is processed at the same time
when it is received
Random & rapid input of transactions
Immediate and direct access to record
29. REAL TIME PROCESSING
Use data as they become available
Receiving and processing of
transaction is performed
simultaneously and there is no delay
This system uses the features of one-
line system
Used in banking for account
maintaining, reservation system in
railways Hotels
30. MULTIPROGRAMMING
There are two main disadvantages of
Batch processing
Under utilization of main memory Main
Memory
Idleness of CPU
Superviso
r
Program-I
Free
Space
31. MULTI PROGRAMMING
Simultaneous Execution of two or
more programs on one computer
system
Computer accesses each program in
turn, loading segments of each
program into separate section of main
storage called partition.
32. MULTIPROCESSING
When two or more processors share
common memory and communicate
with each other, it is called multi
processing
Use of two or more CPUs within a
mainframe
34. TIME SHARING
This system allows different users to
use the same CPU simultaneously by
dividing CPU time among all the users
on a scheduled basis.
Only one CPU
No. of terminals can be more than
100, so it is called as multi access
system
35. CASE STUDY
A Pascal Program is loaded and
executed with the help of operating
system
37. Turn on the
PC
OS
is loaded
Supervisor is
loaded in the
RAM
User enters a
command to load
Application program
The Command is
interpreted by the
command
processor
Supervisor
reads the A.P
into the memory
Control is turned to
command processor which
prompts the user to enter the
command
User wants to read data from
disk, command processor
accepts the command and
assigns job to I/OCS
39. Control is then returned to
load program
The OS now waits for the
next command by user
If files are copied
or updated
Utility programs are
copied to memory by
supervisor