Transcript Additional notes… - University of Texas at Dallas

Chapter 1 & 2 Some additional notes…
(Reproduced from http://www.unix.org/)
Chapter 1 & 2 Some additional notes…
• At AT&T / Bells Labs
– Thomson & Ritchie created the OS for their own personal use
(~1970)
– they needed an OS for their game
“It was the summer of '69. In fact, my wife went on vacation to my
family's place in California.... I allocated a week each to the
operating system, the shell, the editor, and the assembler, to
reproduce itself, and during the month she was gone, it was
totally rewritten in a form that looked like an operating system,
with tools that were sort of known, you know, assembler, editor,
and shell .... Yeh, essentially one person for a month”. Ken
Thompson
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academic and research operating system
Initially, pros: flexibility, extensibility, file sharing
Initially, cons: security, robustness, performance
Initially programmed in “B” (predecessor to “C” language)
• The original version evolved, was re-written in “C” for portability, etc.
Question: Why is UNIX so popular in universities?
• Berkeley Standard Distribution (BSD)
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Derived from AT&T version
freeware! (cheap for universities; only paid for distribution cost)
BSD was first UNIX to include standard network support
enhancements to interprocess communication (IPC), job control, security
• Divergence in the community:
– Many flavours of UNIX in use today: FreeBSD, NetBSD, XENIX,
Solaris, SunOS, HP-UX, Linux, A/UX, AIX, Mac OS X
• Try a google search on “unix operating system version”
Unix Continues to evolve…
Convergence in the community: Single UNIX Specification (derived
from POSIX standard)
What is POSIX?
From http://en.wikipedia.org/wiki/POSIX
• Portable Operating System Interface, with the X reflects the Unix heritage of
the API.
• “POSIX is the collective name of a family of related standards specified by the
IEEE to define the application programming interface (API) for software
compatible with variants of the Unix operating system”
• IEEE standard: IEEE 1003; ISO/IEC standard: ISO/IEC 9945
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The standards emerged from a project, begun circa 1985
Note. You can obtain any IEEE standard from our on-line database via the UTD library
link
Where is the single unix specification?
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The Open group maintains this standard
http://www.unix.org/
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Currently, the standard is at version 3
What are we using?
• SunOS 5.10
• See http://en.wikipedia.org/wiki/Solaris_Operating_Environment for a
brief history of this version (goes right back to an AT&T version)
Question:
• When you log on to the system, how can you tell which version is
installed?
– Command “version” will provide this information
– Also try the commands “uname” and “uname -r”
Some commands to start with…
• Work through the “hands on session” in the book:
– Chapter 1, pages 7-12
– Commands
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date
who
ps
echo
cat, cp, ls, mv, rm
mkdir
pwd
sh
• Slides 11-18 from the book
Some additional commands to start with…
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which, whereis, type
man
more, less
printf
script
passwd
uname
who,whoami
grep
wc