OPERATING SYSTEM

1. PRESENTATION ON
OPERATING SYSTEM & AND
UNIX FOR BCA-IV
AJIT SINGH
ASSISTANT PROFESSOR

2. CURRICULUM
• Operating System Organization and Unix
• External Marks: 80
• Internal Marks: 20
• Time : 3 Hrs

3. Operating System
The operating system is the most important program that
runs on a computer. Every general-purpose computer
must have an operating system to run other programs.
Operating systems perform basic tasks, such as
recognizing input from the keyboard, sending output to
the display screen, keeping track of files and directories
on the disk, and controlling peripheral devices such as
disk drives and printers.

4. Types of Operating Systems
• Multi-user: Allows two or more users to run programs at the same
time. Some operating systems permit hundreds or even thousands
of concurrent users.
• Multiprocessing : Supports running a program on more than one
CPU.
• Multitasking : Allows more than one program to run concurrently.
• Multithreading : Allows different parts of a single program to run
concurrently.
• Real time: Responds to input instantly. General-purpose operating
systems, such as DOS and UNIX, are not real-time.
• Embedded System: The operating systems designed for being
used in embedded computer systems are known as embedded
operating systems.

5. Unix Operating System
UNIX is a powerful computer operating system originally
developed at AT&T Bell Laboratories. It is very popular among the
scientific, engineering, and academic communities due to its multi-
user and multi-tasking environment, flexibility and portability,
electronic mail and networking capabilities, and the numerous
programming, text processing and scientific utilities available. It
has also gained widespread acceptance in government and
business. Over the years, two major forms (with several vendor’s
variants of each) of UNIX have evolved: AT&T UNIX System V and
the University of California at Berkeley’s Berkeley Software
Distribution (BSD).

6. Unix Operating System
• Minix (study OS developed by Andrew S.
Tanenbaum in the Netherlands)
Research Unix-like • Solaris, contains original Unix (SVR4) code
and other POSIX- • Unix (OS developed at Bell Labs ca 1970 initially
by Ken Thompson)
compliant • Xinu, (Study OS developed by Douglas E. Comer
in the USA)
• DesktopBSD FreeBSD distribution for
desktop use
Free/Open source • PC-BSD FreeBSD distribution for desktop use
Unix-like • DragonFly BSD forked from FreeBSD
• OpenBSD forked from NetBSD
Other •TUNIS (University of Toronto)

7. OBJECTIVE
• To hide details of hardware by creating
abstraction
• To allocate resources to processes (manage
resources)
• Provide a pleasant and effective user interface
• Convenience
• Efficiency
• Ability to evolve

8. SCOPE
The next-generation operating system starts with the user. It
ignores the underlying hardware -- and as a result, such systems
are inherently less efficient than today's primitive, machine-
centered ones. Instead, it reflects the shape of your life. Its role is
to track your life event by event, moment by moment, thought by
thought.
A life is a sequence of events in time. The future of information
management is narrative information management, in which all
of your stored documents are arranged as a "documentary
history" of your life.

9. LEARNINGS ADVANTAGES OF OPERATING SYSTEM
Windows
• Openness to virus attacks is a major disadvantage.
• Can be expensive, especially compared to Linux, which is in
most cases free.
Linux
• It is an open source OS, which in most cases is free.
• It is very reliable and rarely freezes.
ADVANTAGES OF UNIX OPERATING SYSTEM
• Virtual Memory
• Toolbox
• Customization
• Portability