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Unearthing Unix History

Warner Losh

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Source: https://www.amazon.com/gp/product/1695978552

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Source: https://www.bell-labs.com/unix50/event/

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Standard History of Unix

Condensed to 3ish slides

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Typical Unix History (1)

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1964 →Join Multics�1969 ←Exit Multics

1969

PDP-7 Unix

1971�PDP-11 Unix

1973 (V4)

C rewrite of Unix

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Typical Unix History (2)

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1975 (V6)�Unix in the wild

and ports start

1979 (V7)�Unix explodes

1983 4.2BSD�Unix gets networking

1984 System V

Unix goes Commercial

1980s

Unix Wars

1990s

Rise of Linux

and FOSS

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Simplified Family Tree

Today’s Talk

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Research Resources

  • TUHS - The Unix Historical Society
  • Bitsavers - scanning and archiving interesting bits of computing history

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The Unix Historical Society (TUHS)

  • Founded by Warren Toomey
  • Outgrowth of the PUPS (PDP Unix Preservation Society)
  • http://tuhs.org
  • Collects all publicly available Unix artifacts in one place
    • Also some private ones that can’t be redistributed (but are preserved)
  • Provides a community for preservation and restoration of artifacts
    • 1972 version of Unix from DECtapes (V2/V3 kernel with surviving V5 disk image)
    • 1st Edition kernel from listings
    • PDP-7 kernel and userland source restoration
    • Some hardware emulation work to run old systems
    • BSD 4.1 restoration from partial copies
  • Pronounced “Toos” or “2’s”

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Bitsavers

  • Dedicated to preserving paper and media artifacts from computing history
  • http://www.bitsavers.org
  • Started by Al Kossow
  • Scanning paper documents for almost 20 years
  • Focused on preserving documentation needed to write emulators
  • Labor of love by Al, although he now accepts well scanned documents
    • And works under the Computer History Museum in Mountain View

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SIMH

  • http://simh.trailing-edge.com to download
  • Emulates most DEC hardware (minicomputers and peripherals)
  • Emulates important non-DEC hardware (mostly mainframes and minis)
    • Interdata (Perkin-Elmer) 16b and 32b systems (First V6 Unix port?)
  • Runs all of DEC’s old operating systems
    • TOPS-20
    • RSX-11
    • RT-11
    • RSTS/e
    • Unix (V4, V5, V6, V7, Sys III and Sys V)
  • Extensive network functionality (including emulators to talk to each other)
  • Written by ex DEC engineer

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Who is AT&T?

  • AT&T is The American Telephone and Telegraph Company
  • “The Phone Company” monopoly in the US through 1982
  • Founded by Alexander Graham Bell
  • Bell Labs is the research group inside of AT&T
  • The Bell System is all the things it took for AT&T to deliver phone service
  • The US is big, so AT&T made most of its money on Long Distance Calls
  • Monopoly consent decree in 1956 made early licensing weird
  • 1982 breakup allowed AT&T to monetize Unix aggressively (System V)

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What’s a PDP-7?

  • “Low Cost” 18-bit mini computers from 60s
  • Mostly binary compatible from model to model

PDP-1 (59)

~10

PDP-4 (62)

~25

PDP-7 (64)

~100

PDP-9 (66)

~400

PDP-15 (70)

~200

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What’s a PDP-11 and/or VAX?

  • 16-bit (PDP-11) and 32-bit (VAX) minis
  • 600,000 PDP-11s and 400,000 VAXen sold

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Ken’s New System

  • Ken loved the game Space Travel
  • GECOS version $50-$75 per game
  • Ken found discarded PDP-7 from Visual and Acoustics Department
  • Ken rewrote GECOS Space Travel in PDP-7 assembler to play
  • Transported binaries from GE-635 to PDP-7 on paper tape
  • Started Ken’s New System to make Space Travel hacking easier
  • Ken also started a Fortran compiler, ended up with writing B...

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http://www.ruddcanaday.com/beat-multics/

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?

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Lost? Not so fast...

  • Robert Morris Sr
  • Bell Labs from 1960-1986
  • Known for crypt, /etc/passwd
  • Passed away in 2011
  • Had large collection of papers
  • Doug McIlroy sorted in 2015
  • Found PDP-7 Unix manuals
  • Posted on https://tuhs.org/
  • Still no source

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Spring 1971�UNIX-7 Late 1969

UNIX-11 Feb 1971

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2016 PDP-7 sources recovered

  • Norman Wilson finds PDP-7 sources
  • Warren Toomey / TUHS “V0 unix”
  • PDP-7 toolchain written
  • PDP-7 “user mode” simulator
  • SIMH enhanced to run pdp-7 unix
  • Userland limited to: adm, als, apr, as, bc, bi, bl, cas, cat, check, chmod, chown, chrm, cp, db, dmabs, ds, dskio, dskres, dsksav, dsw, ed, and mksys
  • init, ln, ls, mv and sh newly written
  • https://github.com/DoctorWkt/pdp7-unix

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Still No working Space Travel

This remains the only Space Travel screen shot we have

Sources build, need full working SIMH Graphics II simulator (coming soon?)

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http://sebras.se/space-travel.png

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Ken’s Discarded PDP-7 was SN 34

$45,000

$32,700

$6,300

$25,800

$7,700

$1,625

$4,100

~$125,000

Total: ~$250,000 1965 Price List

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Could it be?

Conclusion: The PDP-7 in The Incredible Machine looks to be the same one Ken scrounged SN 34...

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Living Computer History Museum boots pdp7 unix

SN 129

Custom JK09 no RC09/RB09

No video display, just TTY

Using TUHS source base

Source: https://www.youtube.com/watch?v=pvaPaWyiuLA at 00:09

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1st Edition PDP-11/20

November 1971

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1st Edition Unix

  • Released November, 1971
  • Supported only the PDP 11/20
  • Transliteration of PDP-7 assembler into PDP-11 assembler (not MACRO-11)
  • We have reconstructed sources, but no tapes from the time remain
    • Only kernel, shell and init survive
  • We have scans of the manual
  • We have scans of Bell Labs slide deck to reconstruct sources

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2nd Edition PDP-11/20 (prep for 11/45)

June 1972

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Source: https://www.tuhs.org/Archive/Distributions/Research/Dennis_v1/

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Typical Unix History (2)

​

1975 (V6)�Unix in the wild

and ports start

1979 (V7)�Unix explodes

1983 4.2BSD�Unix gets networking

1984 System V

Unix goes Commercial

1980s

Unix Wars

1990s

Rise of Linux

and FOSS

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Programmer’s Workbench (PWB)

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PWB - Programmer’s Workbench

  • PWB’s first system installed 1973
    • Canaday, Mashey in BISP division
  • Focused on expanding Unix to being a development platform
    • SCCS (Source Code Control System) originated here
    • Remote Job Entry for various mainframes
    • Make, pwb sh (not bourne), other tools
    • October 1976 CACM had 6 articles on it
  • PWB 1.0 May 1977 (first release outside of bell labs)
    • 6th Edition Unix (plus patches)
    • Typestter C
  • PWB 2.0 1981 (first official release outside of bell labs)
    • 7th Edition based
  • PWB was blended into Unix/TS 3.0 aka System III

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Typesetter C and the “50 changes”

  • After 6th Edition
  • Newest ‘C’ language features, including
    • long, unsigned and union data types
    • Typedef, struct initializers
    • Bit field support
    • Static support
    • Cpp enhancements
  • Dennis Ritchie came up with 50 diffs to take V6 into the then-current Research Unix that were supposedly adopted, at least in part by Unix/TS, PWB and CB-Unix in advance of V7.
  • Similar fixes wound up leaking out of Bell Labs… was an early viral spread of data...

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UNIX/TS

  • Unix Support Group, USG, 1973 Berkley Teague
  • Support focused on using Unix for Time Sharing 4th Edition and newer
  • Started formal releases with 6th Edition
    • V6 + 50 patches + typesetter C UNIX/TS 1.0 (1978)
    • V7 UNIX/TS 2.0 (1979)
  • Merged with PWB and 32V to become UNIX/TS 3.0 aka System III
  • More merges with CB-UNIX to become UNIX/TS 4.0 (never released)
  • UNIX-TS 5.0 merged in pager and became System V

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MERT - Multiple Executive Real Time

  • Approximately 4th Edition Unix (later updated through 6th edition)
  • Unix ran as a supervisor process under MERT
    • Much like today’s paravirtual KVM or HyperV guests
  • MERT allowed real time scheduling and used HW registers for separation

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  • SCCS Unix
  • Evolved into Columbus Unix (CB-Unix)

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Columbus Unix - CB Unix

  • Started in 1971 (1st Edition) for a Switching Control Center System (SCCS!) for a Electronic Switching System (ESS) by New Jersey Bell.
  • Earliest “fork” I could find of Unix
    • Pulled in code from research version frequently in early days
    • Had a lot of Add Ons that were innovative, many appeared in later versions
    • Power-fail restart, tty line disciplines, terminal types and IPC features (1974)
  • Maintained by Division 59473 in Columbus Ohio
    • OSG Operating System Group
  • Widely used for call data systems by different Bell divisions
  • Little known outside of Bell System, mostly lost

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CB Unix Timeline

  • 1971 First SCCS deployed by New Jersey Bell in New Brunswick, NJ
    • First application outside of Research / Patent Office
    • Ran on 11/20 with no memory management
  • 1974 semaphores (Hal Pearson) and tty line disciplines (Bill Snider)
  • 1975 messages and shared memory added (derived from R.J. Purdue)
    • Maus (pronounced mouse) was shared memory, and survived into PDP-11 System Vr1
  • ~1976 CB Unix 1.0 based on 6th Edition Released + local additions
  • November 1979 CB Unix 2.1 released (PWB Unix 1.0 and 7th Edition + local)
  • May 1980 CB Unix 2.3 released
  • 1982 Roger Faulkner merged semaphores, messages and shared memory into UNIX/TS 4.0 (eventually became System V semaphores, etc)

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What Remains of CB Unix?

  • Scan of CB Unix 2.3 Manual
    • Apparent from the SCCS division based on the local manual sections
  • Scan of a kernel source listing
  • A 1984 in net.unix posting by Dale DeJager supervisor of Columbus group
  • Interview mention from Victor Vyssotsky 1985 Unix Review
  • A tape was mailed to Dennis Ritchie before his death
    • TUHS mailing list post from 2003 confirms receipt by Dennis from Larry
    • Current whereabouts are unknown
  • Lots of invocations of its name in ~10 books for System V IPC:

UNIX Network Programming: Interprocess communications, Volume 2

W. Richard Stevens

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Unix

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3rd Edition PDP-11/45

February 1973

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3rd Edition Unix

  • February 1973 (+8 months)
  • “The number of Unix installations has grown to 16, with more expected.”
  • Have both scanned manual and nroff sources
  • A mix of assembler and C
  • Have early C compiler from this release
  • No binary snapshots exist

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4th Edition PDP-11/40, PDP-11/45

November 1973 (+9 months)

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Throw it away… 4th! Rewrite of unix kernel 1973

  • 4th rewrite
    • Pdp-7 assembler (V0 or 0th Edition) 1970
    • pdp-11/20 transliteration (1st edition) 1971
    • pdp-11/45 port (start using MMU) (3rd edition) 1972
    • C rewrite (4th Edition) 1973
      • Kernel remains in C and fundamentally the same through System III (1982)

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4th Edition (November 1973)

  • “The number of UNIX installations is now above 20, and many more are expected.”
  • Only have man page sources from this release (first release typeset)
  • Have a almost 4th edition kernel sources (first one in C)
    • Dates from August 1973, mostly complete, but lacks pipes
    • Recovered from a tape Dennis Ritchie had laying around labeled ‘nsys’
  • Rest of the system is lost
  • Key revision for Bell System adoption and specialization
  • First version released to Universities (4 or 5 universities)
  • USENIX forms

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setuid() in V4 and later...

sys4.c

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4th Symposium on Operating

System Principles

Oct 15-17, 1973

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First Published Unix Paper

July 74 Communications of the ACM

(Abstract in SOSP '73: Proceedings of the fourth ACM symposium on Operating system principles October 1973)

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  • Papers typeset with troff on Unix cite this paper in references
  • Uptick of Unix in the literature begins here
  • Best reference until 1978 BSTJ

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4th Edition Family Tree

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5th Edition Released to The World (PDP-11/70)

June 1974 (+7 months)

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5th edition

  • More universities outside of Bell Labs get this
  • Still exclusively PDP-11 (added PDP-11/70 support)
  • Userland a mix of C and assembler
  • First version with complete surviving sources and binaries
  • PWB / MERT (Unix/RT) / Unix/TS / CB-Unix import this version
  • June 1974

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First MP System

  • System V 4.0MP (1988)
  • AT&T’s OS/370 3B20 Port (1983)
  • Masscomp 7th Edition 68k port (1982)
  • Purdue’s Dual VAX 11/780 (1981)
  • MUNIX (1975)

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MUNIX 1975

  • Likely V5 (delivered fall 1974, V6 May 1975)
    • No known copies survive
  • Dual PDP 11/50 processor
  • Paper talks about semaphores, u areas, etc

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First Network Implementation

  • 4.1aBSD adds sockets with TCP/IP stack (1982)
  • Berknet (1979)
  • Datakit (1979)
  • UUCP (1978)
  • BBN TCP/IP stack (V6 based 1977)
    • surprise: BSD did socket API for 4.1a, but reused descendant of this stack for protocol
  • Terminal Interface Unix MACRO-11 TCP/IP stack SRI/BBN Jim Mathis (1976)
  • University of Illinois NCP stack (late 1974)
    • Modifications to V5 and later V6
  • Spider Cell Network (1973)
    • V3/V4 (Aug 1973) Unix driver available, maybe prior versions had driver (source for them lost)

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Questions

Warner Losh

imp@FreeBSD.org

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For config files and how-to for demos given in this talk, please see

https://people/talks/bsdcan2020/demos.html

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