The document discusses the history and evolution of operating systems from zeroth to fourth generations. It describes the characteristics of each generation including the introduction of transistors, integrated circuits, and large-scale integration. The document also covers the structure of batch systems, advantages of third generation systems, and examples of fourth generation systems like desktop, multiprocessor, distributed, and clustered systems. Finally, it defines the role of an operating system and describes some key services it provides like information management, process management, and memory management.

1. OPERATING SYSTEM

2. HISTORY OF OS
 ZEROTH GENERATION
 FIRST GENERATION
 SECOND GENERATION
 THIRD GENERATION
 FOURTH GENERATION

3. ZEROTH GENERATION
 The first digital computer was designed by charles babbage.
 It had a mechanical design where wheels,gears,cogs,etc.
 As this computer was slow and unreliable.
1791-1871

4. FIRST GENERATION
 These machines were huge and their continued use
generated a great deal of heat.
 The vacuum tubes also used to get burnt very fast.
 The programming was done only in machine language.
 They were single-user machines which were extremely
unfriendly to both users and programmers.
1791-1871

5. SECOND GENERATION
 1995,Transistors were introduced in the USA at AT&T.
 The size and cost of the machine dramatically dwindled.
 Control cards giving information about the job,the user
sequentially stacked
$JOB - specified job to be done
&LOAD -executable machine instructions punched onto them
& loaded into main memory.
1955-1965

6. STUCTURE OF THE BACTH
JOB
$JOB
$END
DATA
$RUN
FORTRAN PROG
$LOAD
USER
NEXT JOB
DATA CARDS
PROGRAM CARDS
CONTROL CARDS

7. THIRD GENERATION
 IBM had designed various computer in this series which were mutually
compatible .
 This is how the concept of “family of computers”
came into being.
 IBM was forced to deliver from operating system .
These were:
 CP-67/CMS for the powerful 360/67,using virtual storage
 OS/MVT for the bigger 360 systems
 OS/MFT for the medium 360 systems
 DOS/360 for the small 360 systems
1965-1980

8. ADVANTAGE/FEATURES /PROBLEM
 Integrated circuits
 Portability
 Job control language
 Multiprogramming
 Spooling
 Time sharing

9. FOURTH GERENATION
 When Large scale integration circuits came into existence ,
Thousands of transistors could be packaged on a very small
area of a silicon chip.
 Made up registers , adders , multiplexers , decoders and a
variety of other digital circuits.
 As the size of a chip containing thousands of transistors
shrank.
 It required tremendous accuracy and reliability.
1980-PRESENT

10. SYSTEMS
 Desktop systems :
Control program for microcomputers(CP/M)
First operating system on the microcomputer platform.
it was developed on intel 8080 in 1974 as a file system.
 Multiprocessor systems:
The uniprocessor system consist of only one CPU ,
memory , peripherals .The SMP architecture , which is
most common architecture for multiprocessor systems

11. SYSTEMS
 Distributed Processing
Distributed processing started becoming a reality. instead of
cenralized large computer , the trend towards having a
number of smaller systems at different work
Two response:
Network Operating System(NOS)
Distributed Operating System(DOS)

12. SYSTEM
 Clustered system:
clustered systems combine best features of both distributed os and
multiprocessor systems. The connected computer systems can be either
uniprocessor or multiprocessor .clustered systems were originally
developed by the DEC in the late 1980’s for the VAX/VMS os.
 Handheld System:
The quest for smaller size of personal computers has spawned an
entirely new type of system over the years known as Handheld systems
. The newton messagepad released by Apple computers in 1993.

13. WHAT IS OS?
 The operating system can be viewed as a set of software
programs normally supplied along with the hardware for the
effective and easy use of the machine.
 The two benefits that enhance its utility are:
- >elimination of duplicate efforts by hundreds of programmers
in developing tedious and complicated routines.
- > provision of security and confidentiality of information to
users.

14. DIFFERENT SERVICE OF THE
OS
 INFORMATION MANAGEMENT
information management refers to a set of services used for storing ,
retrieving , modifying and removing the information on various devices
Create a file
Create a directory
Open a file
Close a file
Read data from file to buffer
Write data from buffer to file
Move the file pointer
Read and return a file status
Create a pipe
Create a link
Change working directory

15. DIFFERENT SERVICE OF THE
OS
 PROCESS MANAGEMENT
The services provided through process management are very
important , if the os supports multiple users as in the case of UNIX or
MVS.
Create a process
Wait for a child process to terminate
Terminate a process
Change a process priority
Block a process
Ready a process
Dispatch a process
Suspend a process
Resume a process

16. DIFFERENT SERVICE OF THE
OS
 MEMORY MANAGEMENT
The service provided under memory management are directed to
keeping track of memory and allocating/deallocating it to various
processes ,
Allocate a chunk of memory to process
Free a chunk of memory from a process