Transcript brief_history - XTR Systems, LLC

Background & History of UNIX & Linux
Fort Collins, CO
The Background and
Short History of
UNIX & Linux
Instructor: Joseph DiVerdi, Ph.D., MBA
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Early Steps
Background & History of UNIX & Linux
Fort Collins, CO
• It is useful to learn the history of OS
– Provides insights into current state of affairs
• "Those that ignore history are doomed to repeat it"
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In the 1960s...
Background & History of UNIX & Linux
Fort Collins, CO
• MIT, AT&T Bell Labs, & General Electric
• Developed an OS Named MULTICS
– Multiplexed Information and Computing System
• Designed to Be an Interactive OS
– Specifically for GE645 Mainframe Computer
– Designed to Allow Information Sharing While
Providing Security
• Development Was Problematic
– OS Was Really Slow to Execute & Required
Extensive Memory
• Bell Labs Pulled Out of Project
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Trouble in Paradise
Background & History of UNIX & Linux
Fort Collins, CO
• In 1969, Ken Thompson
– Bell Labs Scientist Involved With MULTICS Effort
– Wrote a Game for GE 645 Computer
• Called Space Travel
• Program Ran Poorly
– Jerky Performance
• Usage Was Expensive
– Cost $75 Per Run
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Spare Computer
Background & History of UNIX & Linux
Fort Collins, CO
• Program Rewritten to Run on a Spare
Computer
– PDP-7 From Digital Equipment Corporation
– With the Help of Dennis Ritchie
• This Work Provided Thompson With an
Opportunity to Write a New OS
– Multitasking Was Integral
• Soon Other Facilities Were Added
– File System, Command Interpreter & Utilities
• Space Travel Was Added Also
• Many UNIX Features Are Traced to This OS
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A New Name Emerges
Background & History of UNIX & Linux
Fort Collins, CO
• OS Could Support Two Users
– Woo-hoo!
– Advanced for Its Time
• Humorously Named UNICS
– Uniplexed Information and Computing System
– Attributed to Brian Kernighan
• In 1970
– Name Changed Slightly to UNIX
• It Stuck Ever Since
• Progress Was Due to Project's Smaller Scope
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Small Beginnings
Background & History of UNIX & Linux
Fort Collins, CO
• In 1972...
– Second Edition of UNIX Programmer's Manual
• "...There Are Exactly Ten Computers Using UNIX..."
• "...However, More Are Expected..."
• In 1977
– 500 Computers Were Using UNIX
• 125 at Universities
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C Programming Language
Background & History of UNIX & Linux
Fort Collins, CO
• In 1973
– Thompson Rewrote UNIX in Ritchie's C
– C Was Designed to Be Simple & Portable
– C Programs Could Run on Different Computers
• With Little or No Modification
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UC - Berkeley
Background & History of UNIX & Linux
Fort Collins, CO
• In 1973...
– UC Berkeley Ordered a Copy of UNIX
• For Its Shiny New PDP-11/45 Computer
• Purchased for $400 (Including Source Code)
– Two Bright Graduate Students
• Chuck Haley & Bill Joy
– Does CTO of Sun Microsystems Ring a Bell?
• Started Making Modifications & Sharing
• In 1977...
– Free Copies of OS Were Sent Out
– Called Berkeley Software Distribution or BSD
– Included Ethernet & Internet Network Support
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A Split Occurs
Background & History of UNIX & Linux
Fort Collins, CO
• System I, II, III, IV, & V
– Maintained & Supported by AT&T
• 2BSD, 3BSD, 4BSD, 4.2BSD, 4.4BSD
– Maintained & Supported by UC - Berkeley
• AT&T Always Offered Source Code
– Free To Academic Users
• Because of Early Funding Rules
– Expensive to Non-academic Users
• One Goal of BSD - Eliminate All AT&T Code
– Tedious, Difficult, & Time-consuming Process
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Modern UNIX
Background & History of UNIX & Linux
Fort Collins, CO
• End of An Era
– Final From Berkeley - 4.4bsd-lite
– Final From AT&T - System V Release 4
• Computer Manufacturers Created Versions
for Their Hardware
• Software Manufacturers Created Versions for
Others' Hardware
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–
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XENIX - Microsoft & SCO for 80286 & 80386
HP-UX - Hewlett-Packard
Solaris - Sun Microsystems
AIX - IBM
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A Grand Unification
Background & History of UNIX & Linux
Fort Collins, CO
• Several Attempts at Standardization
– Independent Definition of Standard Environment
– Portable Operating System Interface for Computer
Environments
• POSIX
– A Family of Standards Defining
• How Applications Interact With OS
– An Organizing Principle
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Post-Modern UNIX
Background & History of UNIX & Linux
Fort Collins, CO
• In 1991...
– An Unknown Finnish Graduate Re-wrote the UNIX
Kernel From Scratch & Made It Public Under the
New Open Software Foundation Rules
• Linus Torvalds & Linux
– Grown to Full-Featured, Production-Quality Kernel
• Supported by Many Vendors As Primary System
– Big-ticket Commercial Software Packages
• Have Been Ported to Linux
– Oracle & Others
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Example Systems
Background & History of UNIX & Linux
Fort Collins, CO
• Solaris
– Sun Microsystems Hardware
– System V Derivative
• Even With Joy's Presence
• HP-UX
– Hewlett-packard Hardware
– System V & Berkeley Hybrid
• Has Its Own Surprises
• Red Hat Linux
– Intel Hardware
– Torvald's Kernel With Red Hat Components
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