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COP 4604 UNIX System Programming
Introduction
Dr. Sam Hsu
Computer Science & Engineering
Florida Atlantic University
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What Is UNIX?
What is UNIX?
A general purpose, machine-independent,
multi-user (time sharing), interactive
environment.
Creators of UNIX
Dennis Ritchie & Ken Thompson, inspired
by MULTICS.
Received 1983's Turing Award.
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UNIX Features
Some nice features of UNIX
Hierarchical filesystem.
Simple I/O processing.
C language.
UNIX shell.
Pipes/filters.
Designed for programming rather than for
applications.
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Brief History of UNIX (1/6)
Designs of OS used to be hardware-
dependent and implemented in assembly
languages.
In the mid-60’s, people tried to implement
OS in high-level languages.
MULTICS was among the first attempts.
Coded in PL/1, designed at MIT.
Was judged a failure, even though the idea
was considered innovative.
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Brief History of UNIX (2/6)
Dennis Ritchie and Ken Thompson continued;
they pioneered a project known as UNIX.
A pun on MULTICS.
UNIX was first developed on PDP-7, written in
PDP-7 assembly language.
Was rewritten almost entirely in C in 1972.
Was initially developed at Bell Labs for
their own in-house use; however, found a
way to escape from Bell Labs starting in
1974.
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Brief History of UNIX (3/6)
In 1974, Version 5 was licensed virtually free
to universities.
The University of California at Berkeley was
among the first schools that received the
earliest academic licenses.
Version 6 was announced in 1975.
One copy was licensed to the Rand Corporation
The first commercial version ever sold.
