UNIX
Introduction
U.Y: 1435/1436 H
What is Unix?

UNIX (pronounced “yoo-nicks”) is a computer operating
system - the set of programs

that controls the rest of a computer system.

It allocates the computer's resources and schedules tasks.

It allows users to make use of the facilities provided by
the system.
What is Unix?

UNIX is a multi-user, multitasking operating system.
•
Multiple users may have multiple tasks running simultaneously.
•
This is very different than some other operating systems.

UNIX is a machine independent operating system.
•
UNIX is not specific to just one type of computer hardware.
•
UNIX was designed as a software development environment.
UNIX v.s. Unix

UNIX is a trademark, owned by AT&T, and then by USL,
and then byNovell.

Unix refers to an operating system which is “UNIX-
like” - it looks and feels like UNIX, but it is derived
independently of the proprietary source code.

To name something UNIX you have to follow the Open
Group specification, and pay the use of the trademark
Unix History

1965: Bell Laboratories, MIT, and General Electric begin
the development of Multics – (Multiplexed Information
and Computing Service) which was to provide support
for multiuser systems, multiprocessor capabilities, and a
multilevel file-system.
Unix History

1969: AT&T was unhappy with the progress on the
Multics project. Ken Thompson, Dennis Ritchie, Rudd
Canaday, and Doug McIlroy designed and implemented
the first Unix file system, and a few utilities. Brian
Kernighan dubbed the new OS “UNIX” (UNiplexed
Information and Computing System) (a somewhat
treacherous pun on Multics).
Unix History

January 1, 1970:Time zero for Unix.

1975: AT&T makes UNIX widely available - offered to
educational institutions at minimal cost. Becomes popular
with university computer science programs.
Unix History

1984 to date: University of California, Berkeley adds
major
enhancements,
creates
Berkeley
Standard
Distribution (BSD).

1984 to date: Many Berkeley features incorporated into
new AT&T version: System V

UNIX becomes the operating system of choice for
engineering and scientific workstations.
Unix History

Two variations maintain popularity today, AT&T System V
based and the Berkeley Standard Distribution (BSD).
Unix Variants

You may hear people talking about Unix, Solaris, Linux,
BSD, System-V, among names used to describe Unix
systems.

Over time, vendors and researchers have developed their
own variants.

What is the difference between these operating
environments?
•
For regular users, differences tend to be small.
Tree of Most Famous Unixes
Why study Unix?
Why study Unix?

So why would someone choose Unix over Windows,
MacOS-X, DOS, Plan-9, or some other operating system
environment?

Unix is one of the most widely used operating system in
the world. It has been ported to run on a wide range of
computers, from hand-held devices (e.g., Android) to
supercomputers.
Why study Unix?

Unix ensures hardware independence – the operating
system code is written in C language rather than a
specific

assembly language.
Operating system software can be moved from one
hardware system to another.

Unix applications can be easily moved to other Unix
machines. Porting is usually as simple as transfer the
source and recompile.
Why study Unix?

Productive environment for software development

Rich set of tools

Versatile command language

Unix is available at virtually all software development
centers, universities, and High Performance Computing
(HPC) centers.

Unix
has
advanced
multitasking capabilities.
distributed
processing
and
Why study Unix?
Refernces

https://www3.nd.edu/courses//cse/cse20189.01/www/