Operating Systems Types

1. Presentation
Topic “Time SharingSystem”
Jamshaid Ali(2011-COE-10)
Sohaib Abdullah(2011-COE-19)

2. TYPES OF OPERATING
SYSTEM

3. Presented By:-
Yousuf Nazir 2011-COE-17
M.Ishfaq Shah 2011-COE-23

4. Operating System is a software, which
makes a
computer to actually work.
It is the software the enables all the programs
we use.
The OS organizes and controls the hardware.
OS acts as an interface between the
application
programs and the machine hardware.
Examples: Windows, Linux, Unix and Mac
OS,
etc.,

5. What OS does?
An operating system performs basic tasks
such as,
controlling and allocating memory,
prioritizing system requests,
controlling input and output
devices,
facilitating networking.

6. Providing user interface
 Two most common types.
1) GUI (Graphical user interface)
1) Command line interface

7. GUI
 A GUI uses windows, icons, and
menus to carry out commands such
as opening files, deleting files, moving
files, etc.
 Many GUI Operating Systems are
operated by using a mouse, the
keyboard can also be used by using
keyboard shortcuts

8. GUI
 System 7. xp
 Windows 98
 Apple System 7 and Mac OS X

9. GUI

10. CLI
 Referred to as the command line
interface or a text interface.
 Navigated by typing commands at
prompts.
 Uses a keyboard to navigate by entering
commands and does not utilize a
mouse.

11. CLI

12. Types of o.s
Batch system
Real time o.s
Single-user/single tasking
Single-user/multitasking
Multi user/multitasking
 Time sharing system

13. Batch System
 Such systems in which the user does
not get to interact with his/her jobs and
jobs with similar needs are executed in a
“batch”, one after the other, are known
as batch systems.
 drives as input devices are line
printers, tape drives, and card punches
as output devices.

14. Batch System
 All FORTRAN programs were
complied one after the other. The major
task of such an operating system was to
transfer control automatically from one
job to the next.
 In this execution environment, the CPU
is
often idle because the speeds of the
mechanical I/O devices such as a tape
drive are slower than that of electronic
devices.

15. Real Time
System
A real-time system is
one that must process
information and
produce a response
within a specified time.

16. Real Time System
 Any system in which the time at which
output is produced is significant.
 Time an important factor.
 That is, in a system with a real-time
constraint it is no good to have the
correct action or the correct answer
after a certain deadline.

17. Types of Real Time System
 Soft Real Time System
all practical systems can be said to be real-
time systems because they must produce
an output or respond to the user’s
commands within a reasonable amount of
time.
However a small delay is bearable.
(insurance company responding to
letters, word processor displaying what
was typed on the screen, mobile phones
responding)

18. Types of Real Time System
 Hard Real Time System
Systems where failure to meet
response time constraints leads to
catastrophic system failure.
Modern world interested in these
systems.
(aircraft crashing, car
skidding, patient dying before
corrective action is performed)

19. Single user/Single
tasking OS
One user works on
the system
Performs one task
at a time

20. Single user/Single tasking OS
One user works on the system
Performs one task at a time
MS-DOS and Palm OS
Take up little space on disk
Run on inexpensive
computers

21. Single-user/multitasking
User performs
many tasks at
once
Most common
form of OS

22. Single-user/multitasking
They are popularly
associated with Desk
Top operating system
which run on
standalone systems
where no user
accounts are
required.

23. Single-user/multitasking
 They may run different types of
operating systems, including
DOS, Windows, and Mac OS. Linux
and UNIX operating
 Operating System can take control
back from the running process and
can give it to other.

24. Single-user/multitasking

25. Single-user/multitasking
 When one job needs to wait for I/O, the
processor can switch to the other job

26. Multi user/multitasking
 Allows two or more users to run
programs at the same time.
Many users connect to one computer
 The operating system keeps
several jobs in memory
simultaneously
 Some operating systems permit
hundreds or even thousands of
concurrent users.

27. Multi user/multitasking
Each user has a
unique session.
Requires a powerful
computer

28. Multi user/multitasking

29. Time sharing System
 Time-sharing or multitasking is a
logical extension of
multiprogramming.
 Provide advantage of quick
response.
 Reduces CPU idle time.

30. Time sharing System
When the time runs out, the process is
interrupted, and another process is
loaded into the CPU.
 The act of giving each process a small
slice of time to run is called time slicing.

31. CPU Time Slicing
for Time Sharing
CPU
Process 1
Process 3
Main Memory
Process 2Current
Process
Repeat until all processes have completed.
Allocate CPU to
Process 1
Allocate CPU to
Process 2
Allocate CPU to
Process 3