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Operating System
Part II: Introduction to
the Unix Operating
System (The
Evolution of Unix)
Introduction to the Unix Operating
System
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The Evolution of Unix
Utilities and Shell Programming
Systems Calls
The Evolution of Unix
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First version was developed by Ken
Thompson (1969) being part of the Research
Group in Bell Laboratories
Developed in PDP-7 (which was idle at that
time)
Soon joined by Dennis Ritchie (worked on
MULTICS)
The Evolution of Unix
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Thompson and Ritchie worked for so many
years
Moved to PDP-11/20 for the second version
Third version: used C (developed in Bell Labs
to support Unix) instead of assembly language
The Evolution of Unix
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Multiprogramming and other enhancements
added when the system moved to PDP-11/45
and PDP-11/70 (both hardware support
multiprogramming)
Version 6 (1976): first version distributed
outside of Bell Labs
The Evolution of Unix
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Version 7 (1978)
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Developed for the PDP-11/70 and Interdata 8/32
Considered “ancestor” of most modern Unix
systems
Also ported to VAX (appeared as 32V)
The Evolution of Unix
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Because of clean design of early Unix Systems
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Led to Unix-based work at other computer science
organizations
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Rand, University of Illinois, Harvard, Purdue
University of California in Berkeley (most influential nonBell, non-AT&T)
The Evolution of Unix
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1978
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First Berkeley VAX Unix work (addition of virtual
memory, demand paging, & page replacement to
32V
Bill Joy & Ozalp Babaoglu worked together to
produce 3BSD (BSD - Berkeley Software
Distributions) Unix
First implementation of such functionality
Allowed large programs to run in Unix
The Evolution of Unix
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Memory management work convinced DARPA
(Dept. of Advanced Researched Projects
Agency) to fund Berkeley
Develop standard system for government use
The Evolution of Unix
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Project led to release of 4BSD
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Supported by notable people from Unix &
networking community
One of the goals is provide networking for DARPA
Internet networking protocols (TCP/IP)
The Evolution of Unix
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Release 4.2BSD
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Possible to communicate among diverse network
facilities (LANs, WANs)
Adopted features from contemporary O/S (new user
interface -- C shell, new text editor -- vi, etc.)
Culmination of original Berkeley DARPA Unix
project
The Evolution of Unix
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Release 4.2BSD (continued)
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Reason for current popularity of mentioned
protocols
1984 -> 60 connected networks
1993 -> 8,000 connected networks, 10 million users
The Evolution of Unix
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1993 -> 4.4 BSD
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last Berkeley release
includes x.25 networking, new file system
organization, enhanced security, improved kernel
structure
Berkeley stopped its research after this release
The Evolution of Unix
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Currently not limited to Bell, AT&T, Berkeley
Moved to many different computers
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Sun Microsystems ported BSD to their workstations
DEC - Ultrix, OSF/1
Microsoft Xenix; Windows/NT heavily influenced by
Unix
Santa Cruz Operations - SCO Unix (PCs); Linux
(Red Hat, Caldera, etc.)
The Evolution of Unix
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Many standardization projects for Unix
environments
IEEE, ISO, ANSI, etc.
1989: ANSI standardized C programming
language (ANSI C)