First presented June 10th 2007 at Vintage Computer Festival East 4.0 at Infoage, titled "30 years of CP/M", by Herb Johnson. Also presented at University of Deleware / Newark in Oct 14 2007 for course on computer history and restoration. Most recent revision of this expanded version is Feb 03 2009, some fixes in June 2011. - Herb Johnson
Overview: We make the case that the work of Gary Kildall and his colleagues and clients in the early 1970's, produced an operating system (CP/M) and a collection of software tools which set THE STANDARD for subsequent personal computing. This standard, with other standards such as the S-100 bus, BASIC, video display and floppy drives, provided uniform technology for the foundation of the early personal computing marketplace. These standards enabling individuals and small companies to become productive and successful, using well-known and portable technologies. This market base supported the later entry of major companies like IBM who nonetheless had to provide products consistent with these standards and software products.
This presentation only covers the origins and development of CP/M-80 in the 1970's, but references past and later activity. Many individuals named, including Kildall and Torode, have not recieved the attention they deserve for this early and essential work. Original publications and first-person references are available to date key events, companies and products.
Contents (c) Herb Johnson 2008, referenced works copyrights by respective sources and authors. More information is available on my Web site for early Digital Research CP/M products and development at the link below, which references other Web pages and documents at my CP/M home page.
...on IMSAI is available on my IMSAI Web page
...of John Torode's Digital Systems and the first S-100 and CP/M floppy product is on its own Web page
...of Gary Kildall's Digital Research and the first CP/M, is on its own Web page.
...of floppy controllers for Torode's Digital Systems, IMSAI and Kildall, MITS's Altair, and iCom is on its own Web page.
...of the world of S-100 systems, my collection of S-100 documents and information on its own home Web page.
Learn more about my Retrotechnology.com Web site and technology history from linkes on my domain home page. Contact me from my business inquiry page.
Herb Johnson
I. The "digital" world of 1970 - computers very remote, large, expensive, rare
computing
Mainframes: IBM and PL/I. Expensive, rare
Timesharing and the PDP-10:
FORTRAN and tools. not cheap, rare
algol
minicomputers: control, data collection. $50K a bargain
accountants, engineers, scientists only
information technology barely "digital"
paper-based: books, magazines, newspapers;
punchcards, papertape, index cards
II. Digital electronics of early 70's, Kildall and colleagues
early 70's digital world
digital logic chips, hundreds per system
IMS Associates, MITS in 1973: digital design
DEC: "flip chip" logical design in hardware
beginnings of microprocessors: Intel's 4004, 8008
logic replacements for mechanical controls
1971: IBM "flexible disk" microprogram loader - the floppy disk drive
for use in minicomputers by 1973 (Computer Design June '73)
Kildall et al, microprocessors, design, and CP/M in the early 70's:
limited function processors 4004 in 71, 72
John Torode: '72 PhD at Univ of Wash
Theodore Kehl: '61 Ph.D, joins U of W in late '60's. "mentor" of Torode
Kildall as student at Univ of Wash
'71: writes XPL compiler for Algol on Burroughs m/f
"heathkit" article on modular approach, standard tools
PhD in May 72, XPL and ALgol compilation
value of high level languages
Kildall as faculty member, Naval School in '72
starts MAA for consulting work at Intel
uses 8008 as logic replacments using PL/M
tools for editing files, debugging programs
PL/M: via XPL, from Algol and PL/I
paper tape editor
III. mid-1970's: microprocessor advance, Kildall moves to 8080 with more native tools
1973:
Intel SiM-08 single board as breakthrough
Claude Kagan's Home Reckoner article predicts personal computing
Mar: Electronics article, "Microcomputers muscle in"
processors as logic controllers
Intel, Fairchild, National, Rockwell
Kildall works on (8008?) Computer Cast horoscope machine
a test bed for native development tools
Kildall works for Intel:
Kildall wrote Intel's PL/M 08, released June 1973 (see Wescon '74 article)
8008 cross assemblers, cross compiler
receives Intel Intellec 8 (8008)
Intel's 8080 announced, Kildall upgrades 8008 tools
Shugart floppy diskette drive, first CP/M coding
"to support a resident PL/M compiler", does floppy controller design
Nov: Torode & Kehl wrote logic machine modular design system
published one year later in IEEE Trans. on Computers
microprogrammed computer general design for specific uses
Kildall pitches CP/M to Intel: no deal
1974: Kildall gets 8080 upgrade to Intellec 8/80: PL/M for 8080, works on CP/M
Feb: Kildall writes article on PL/M 80 for Wescon '74
June: Kildall develops and publishes about 8080 application for (water) diving project
July: Jon Titus and Mark-8 8008 system on Radio Electronics cover
NCC '74: floppy controller how-to
Aug: Kehl, Moss, Dunkel: automated digital design
Sept: disk OS and floppy controller from ICOM
also see this iCOM Web page
Kildall and Torode at work "in the fall of 1974"
Kildall says Torode "completed his controller"; Torode says he "replaced" Kildall's controller.
Kildall's disk operating system "completed by 1974"
see discussion on this Web page
Kildall NCC '75 checkpoint paper:
page 99
page 102
8080 board
CP/M system?
late 74: MITS' Ed Roberts gets deal on 8080's, designs Altair 8800
1975-76: what was expected market for microprocessors? not much compared to TV's.
Jan 8 1976 report by Electronics Magazine:
USA Consumer electronics market was/would be
$7B in 1974, $6.5B in 1975, $7.5B in 1976, $10B in 1979
about 50% TV's, 30% audio, 15% other consumer items
$1B to $2B in integrated circuits, microprocs $45M in 1974 to $500M in 1979!
Microcomputers? 20M in 1974 to $500M in 1979
in a data processing market of $17B in 1974 to est. $27B in 1979
minicomputers (<$50K) alone: $600M in '74 to $1.1B in '79
data terminals: $900M in '74 to $1.6B in '79
IV. 1975 and it all breaks loose
1975: the early tools and products are developed
Jan 75: Popular Electronics, MITS Altair 8800 cover
early '75: IMSAI wants Altairs for hypercube, no deal
Joe Killian decides to design similar unit
advertized IMSAI 8080 in summer '75 Popular Electronics
developed, shipped in Dec - $400
Mar 5 75: first meeting of Homebrew Computer Club in California
several S-100 developers-to-be were members
Kildall adds to OS an editor, assembler, debugger
Intel turns down Kildall's offer of CP/M
Torode's Digital Systems licenses CP/M to LLNL and Omron
Kildall and wife found Digital Research to develop and sell CP/M
NCC '75: Kildall "microprocs as logic elements" under PL/M
late '75: Gordon Eubanks completes BASIC-E compiler
as MS thesis under Dr. Kildall; releases use to general public
late '75: Torode's Digital Systems floppy controller w/ "CP/M" for Altair
which uses a microcontroller design
compare to 1973 Torode/Kehl design
see for Torode's Digital Systems products
Multibus and ISIS from Intel for 8080
ISIS commands: DIR, COPY, DELETE, ATTRIB, DEBUG
8080 assembler "written in PL/M"
only runs on Intel system, possibly only Multibus
development only, not an application OS
see the "race" for floppy controllers in 1975-76
1976: microprocessors advance, things get cheaper including floppy drives
many kinds of microprocessors available:
see this list of 36!
prices drop, for instance on the 6800 in April
Zilog offers Z80 processor in Jan article
more disk OS's and floppy controllers:
MITS Mar 76 announcement,
floppy controller with disk BASIC.
ICOM Jan 1976 ad,
iCOM developes S-100 floppy subsystem with FDOS by Sept 76,
check this iCOM Web page for evidence
Nov?: Persci 1070 "intelligent diskette drive controller"
serial interface for ASCII disk OS commands, I/O interface for data.
Sykes floppy ad for Feb 1976
June: Kehl, Dunkel; simplified floppy contrl design
summary here
CDOS written by Cromemco when no CP/M help given
more cross compilers for PL/I-like languages
Feb: Motorola's MP/L for 6800
April: Intermetrics PL/M 6800
June: signetics PL/M+ for 2650
also: MCT cross-assemblers, 6800 & F8 boards
National PL/M+ for PACE, IMP-16 (1975)
more 8080 systems
Intel's ISIS and Multibus 8080 cards & systems
The Digital Group (multiple procs) see my Web page on this
more plug-compatible cards for systems
Feb: MITS offers Altair, (Microsoft) BASIC, I/O cards in ham magazine ad
8800 at $439 kit $621 assembled
4K DRAM board $195 kit $295 asmbld
serial or parallel I/O board $115 kit $144 asmbled
4K BASIC $60 and up
more "Altair/IMSAI compatible" products from others
June: IMSAI prices rise, floppy controller announced in ad
other processors:
Mos Tech 6501, 6502 in Oct 1975
June: SWTP 6800 system SS-50 bus
feb: KIM-1 offered
minicomputers fight back: cheaper, more software
typical ad by DEC for LSI-11
V. CP/M in early use
1976 as word gets out
April DDJ: "First Word on a floppy-disc operating system" by Jim Warren
Digital Research, CP/M by name; products already a year old
ED, PIP, CCP commands by name
$70 for CP/M, controller $100-$350, drives $550-$650
Aug DDJ: "The time for Floppy's is Just About NOW!" by Jim Warren
Torode's Digital Systems floppy controller w/CP/M "available"
Personal Computing '76 and the S-100 name alledgely appears
late 1976: CP/M V1.3 for IMSAI by Kildall and Glen Ewing
1st gen IFM/FIB floppy cntrl w/8080 proc
seperate BIOS emerges
Nov/Dec DDJ: "Upgraded CP/M floppy disc operating system now available"
purchased by Robert Swartz in late 75 - early 76 "no trouble with it"
**CP/M as a product**: the CP/M ad in December 1976 BYTE magazine
DRI's CP/M ad: w/ essential features:
complete: an OS, editor, assembler, debugger, batch
adaptable: to any 8080 system with diskette drive, *by the user*
mature: almost two years field use
cheap: $70 per system, with docs
1977 and CP/M products
**CP/M hardware and S-100 support** Jan BYTE:
Torode's Altair/IMSAI floppy controller with CP/M
$1595 as 2-card set
third CP/M license **sold to IMSAI** for IMDOS & 2nd gen cntrl DIO/PDS
MITS sold to Pertec, expands product line
July 1977: Date on Digital Systems (Torode) version 1.4 S-100 interface schematics to his floppy controller
1978:
1978 S-100 Inc. catalog includes Digital Systems floppy controller
Feb: IMDOS 2.02, IMDOS 2.05 by IMSAI
CP/M 1.4 in general release and for Cromemco, other companies
Feb: Eubanks' Complier Systems and IMSAI offer CBASIC product.
IMSAI pays Gordon Eubanks to write CBASIC for license to distribute it.
CP/M 1.4 of 1978 - a complete product
fundamental tools: OS of BDOS, CCP, BIOS, tools of assembler, editor, debugger
CP/M 1.4 documents:
intro to features & facilities" cover CCP and tools
interface covers programming from PL/M view
(interface contents)
ASM, DDT, ED books
VI. 1978-79: CP/M refined and in larger release
1979: Kildall's DDJ article "The Evolution of an Industry: One Person's Viewpoint". (pub. Jan 1980)
Kildall reviews his earliest work on CP/M through IMSAI and version 1.3.
major revision CP/M 2.0 available: more disk features from BDOS into BIOS
minor revision fix 2.2, became next generally available DRI product
CP/M 2.2:
"intro" not greatly changed
"interface" expanded BDOS call descriptions
new "Users Guide": enhancements, BIOS descriptions, diskdef's
new Alteration Guide to build new BIOS, gen it, BIOS source
NO PL/M CODE discussed, assembler examples only
VII. Microcomputing in the late 1970's: general "personal" and business computers
more powerful microprocessor systems
more storage, more speed, more memory
resident compilers/interpreters including BASIC, C, Pascal
programs for non-programmers: word processing, spreadsheet, etc.
move from multi-board to single-board computers
standards
CP/M & floppies
Z80 & S-100 bus
CBASIC and Microsoft BASIC
...yet other standards, other processors
spread of technology from the bottom up, not yet top-down
disk libraries
clubs, newsletters, magazines
BBS and dial-in systems
hobby and engineering, to business and personal
VIII. CP/M development after CP/M 2.2 and after the IBM PC
1980: DRI's MP/M for 8080 introduced.
June 1981: Kildall's BYTE article: "CP/M: A Family of 8-and 16-Bit Operating Systems"
history of PL/M and early CP/M
CP/M, MP/M CP/NET, native PL/I - all 8080
CP/M-86, MP/M-86 mentioned in passing by DRI
Kildall says 16-bit processors "already outmoded"
1981: DRI buys Eubanks' Compiler Systems and CBASIC
August 12 1981: IBM press release for the 5150 "IBM PC"
$4400 with OS, two floppies, video monitor: not cheap
OS, software, features all derived from current technology
documentation like any other microcomputer of 1981
open software sources, like any other microcomputer of 1981
Kildall's DRI fails to reach terms with IBM
Microsoft "PC-DOS" based on Seattle Computer Systems OS, largely CP/M-80 in design
disagree? tell it to the court!
BASIC a long standing product from Microsoft
IX. Summary: CP/M and DRI evolutionary history
Kildall as developer and teacher, using mainframe-based tools
asssembler and PL/M as tool set for Intel 8008, 8080
native 8080 assembler, editor, debugger developed in PL/M
OS developed to run the tools on floppy drives
OS honed on early IMSAI
CP/M 1.4 as fundamental tools,
some resident on 8080, some in PL/M
limited ability to handle disk formats, embedded in BDOS
CP/M 2.2 as a general-purpose, all-native OS development system
no PL/M needed, no OS source needed
handles multiple disk formats in BIOS
1970's later products with more power for more hardware
CP/M 3.0, MP/M for 8080,
GSX for graphics, CP/NET for networking & for slave CPU's
C and PL/I languages
1980's:
Torode's Digital Microsystems develops Z80, 8086 systems, Hinet local network
ultimately sold to Apricot Computers in the UK for networking
8086 versions for IBM PC and PC compatibles
task switching and windowed products, 286/386 support
1990's:
1991: DRI sold to Novell Inc. for $120 millon.
see Business Week article of Oct 25, 2004
later sold to Caldera, who later buys SCO.
late 1990's: Caldera CEO Brian Sparks licenses CP/M to Tim Olmstead
archive of early CP/M for personal use
collects code and docs, offers freely on the Web
21st century:
Sept 2001: Olmstead developes archive. Died 9/11/01 of cancer
Oct 2001; Lineo CEO Brian Sparks licenses Gaby Chaudry
"unofficial CP/M Web site" maintains archive, adds more
DrDOS Inc. (Sparks) buys all DRI rights.
2006-07: Udo Munk revives CP/M emulator Z80PACK, verifies CP/M sources
wraps early CP/M, 1.4, 2.0 with ISIS tools, PL/M
X. Where are they today?
Gary Kildall & CP/M
CP/M properties eventually sold to DRDOS Inc., active to this day
Kildall died in 1994
John Torode
Digital Microsystems Inc in 1979,
developed Hinet local area network, sold DMS in 1986
co-founded IC Designs with Theodore Kehl
IC Designs merged with Cypress Semiconductor, Torode on Board
both Torode and Kehl distinguished alums of U of W
Al Shugart
Shugart Associates, then Seagate.
w/ Seagate until 1999, Al Shugart died Dec 2006
Gordon Eubanks: see this link
co-developes Q&A database product; financed to run Symmantic which sells it
Symmantic does well, acquires Peter Norton, Central Point. Major company in 2007.
MITS:
MITS bought by Pertec in 1977; last production mid-78
Dr. Ed Roberts becomes an M.D. in private practice, then retires
Pertec may have lasted through early 90's?
Altair originals, replicas, emulators available
IMSAI:
Bill Millard founded Computerland, strange tales ensue
1979 IMSAI bankrupcy sale: inventory to Fulcrum, WW Component; products to Fischer-Freitas
since 2001 imsai.net by Todd Fischer
originals, emulators and major revisions of products available
Intel:
ended support for ISIS, MDS in 1993? (Hitex)
sold Multibus to Radisys in 1999, to UST in 2001
ownership of s/w not clear
iRMX supported by Tenasys
emulation for ISIS, MDS support from Hitex Ltd.
ISIS emulator for MS-DOS as somethingware
Microsoft:
some deal in 1981 with IBM - ???
still in business
Gates retires in 2008
Contact information:
Copyright © 2011 Herb Johnson