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Chapter 7 1972- 1977

Chapter 7 1972- 1977. The Personal Computer. Paul Ceruzzi. “The development of personal computing followed a trajectory that is difficult to explain as rational.”. Mark Twain.

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Chapter 7 1972- 1977

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  1. Chapter 71972- 1977 The Personal Computer

  2. Paul Ceruzzi “The development of personal computing followed a trajectory that is difficult to explain as rational.”

  3. Mark Twain “Very few things happen at the right time, and the rest do not happen at all. The conscientious historian will correct these defects”

  4. “Ready or not, computers are coming to the people. That’s good news, maybe the best since psychedelics.” Stewart Brand- Stanford Rolling Stone Magazine December 7, 1972 “Spacewar: Fanatic Life & Symbolic Death Among Computer Bums”

  5. TOPS-10 & PDP-10 • PDP-10  large mainframe • Spacewar & Time-sharing @ Stanford • Good operating system + disk • 1972  TOPS (@ MIT) • Timesharing operating system • Description Pg. 209 • Sounds like… DOS • Though mainframe, “it was personal” First PDP-10

  6. TOPS-10 (cont.) • PIP - Peripheral Interchange System • Moved files to and from I/O devices • TECO - Text editor & corrector • Text editing from a terminal • DDT - Dynamic Debugging Tool • From terminal • Simple and elegant: user “in control”

  7. Early Time Sharing • Scientific Data Systems (SDS) • SDS-940 – did well in market • Berkeley, ARPA • Bought by Xerox • Xerox PARC • MAXC-Multiple Access Xerox Computer • A PDP-10 clone • Tymshare, CA • One of the few companies that leased time and survived • Bought by McDonnell- Douglas

  8. Personal Computing • Chuck House, Hewlett Packard RE: Calculators “One could charitably say we invented nothing: we simply took all the ideas that were out there and figured out how to implement them cost effectively”

  9. Personal Computing (cont.) • Gordon Bell “The semiconductor density has really been the driving force, and as you reach different density levels, different machines pop out of that in time.” • Would personal computing arrive top-down or bottom-up?

  10. Personal Computing (cont.) • 1st mainframes operated as personal computers • LINC; MIT & Lincoln Labs • 1962, DEC • Late 1960’s – 1,200 in use • Personal tool for researcher • LINC + PDP-8 for $43,000

  11. Calculators • Chip density made electronic calculators feasible & affordable • Early ones: +,-,*,/, square root • Too big to carry, very expensive • 1964-Wang 300-undercut price • HP-9100A- $5,000 • Olivetti- Programma 101- $3,500 • Still used discrete circuits, tubes, cards (magnetic) • 1970’s – began to use ICs

  12. Calculators of 1970’s • IC’s; $400+; size of paperback • 1971- Bowmar Brain - $250 • 1st real public notice • Prices dropped • 1972- $150 • 1973- $100 • 1976- $50 • HP35 - $400- scientific, engineering

  13. Calculator Trends • Became “throw-away” items • HP & TI survived • HP – engineering & scientific • TI – cut prices • HP-65 – programmable • Marketing - “personal computer”

  14. Impact of Calculators • Long production run • Allowed companies to amortize high design costs • Unleashed personal creativity of masses • Hacker culture but professionals • Users groups, etc. for support • Chips were too specialized for general purpose computing

  15. People • Hackers • Did impact industry • Serious Users had money • Altair Kit • User Groups • Homebrew Computer Club-Stanford • Tech Model Railroad Club

  16. Moore’s Law • 1964- Gordon Moore • Fairchild  formed INTEL • Since 1958, number of circuits on a single integrated circuit have doubled each year • Predicted: by mid-1970’s would have single chip equivalent to 1950’s mainframe

  17. Computer on a chip??? • Late 1960’s; TTL & MOS (metal oxide semiconductor) • More density • TI, Intel, and others • Generally believed “computer on a chip” was feasible, but market too low to be profitable • 1971 - Silicon chip • TI, Intel

  18. Invention of Microprocessor • Intel - Focus on memory, not logic chips • Busicom, Japan, Calculator Co. • Wanted set of custom logic chips for line of specialized calculators • Ted Hoff- assigned • Inspired by PDP-8 • Design few general purpose chips & tailor with software

  19. Hoff’s Logic Chip • All components of general-purpose computer • Patent Diagram Pg. 219 • Critical feature: subroutine call • Used stack for multiple calls • Slow; but plenty fast for calculator • Complexity in the software in memory • Recall Maurice Wilkes

  20. Intel’s Microprocessor • Negotiated lower price to Busicon for rights to sell chips to non-calculator customers • 1971- set of 4 chips • “A micro-programmable computer on a chip” • 4004:registers & control function • ROM (EPROM) • RAM • Chip for output

  21. Intel 4004-8008-8080 • 4004; 1971 • Worked with groups of 4 bits • Much question over patents (2) • 8008; 1972 • For Computer Terminal Corp (later Data Point), San Antonio – for terminals • Chose another chip • Worked with 8-bit byte • Others now offering processor chips

  22. Intel (cont.) • 8080; 1974 • More memory • near compatibility of mini • Less support chips • $360 (?Why?) • Compatible with 8008 • Instruction set, memory range similar to minicomputers

  23. Intel’s Early Chips Intel’s 4004, 8008, 8080 Chips

  24. Early 1974 Climate • Semiconductor engineers  powerful microprocessors + larger memories • Time-sharing users * Did not see the convergence coming

  25. MICRAL-1973 • 1st micro-processor-based computer sold commercially • Thi Truong- France • Based on 8008 • < $2,000; 2000 sold • Replaced mini’s for control systems • Never expanded market

  26. Intel Development System • Kit: RAM, ROM, + control on a circuit board • Tutorial • $200 or free • Industrial customers developed applications & burned on ROM - Embedded Controller

  27. Intel System (cont.) • Intellec 4 & 8 • $10,000 • Develop software- PL/M • Were PC’s, but not recognized • Not available to public • “public wouldn’t want to do programming”

  28. Hobbyists Get Involved • There were hobbyists who were willing to micro-program • After WWII- Electronics hobbies grew • Expertise and war surplus • Electronics magazines • QST; Popular Electronics, Radio- Electronics • Typically included a project

  29. Kenbak-1 • Scientific American • Sept. 1971 • For private use & schools • Small & medium scale IC’s • No Microprocessor • Very limited capabilities

  30. Scelbi - 8H • March 1974 - QST • Intel 8008 • 1st microprocessor sold to public • Kits as low as $440

  31. Mark -8 • Radio- Electronics • July 1974 • Intel 8008 • Had to order $5.00 booklet • Sold thousands • Mark-8 Users Group, Denver • Stored programs on audio cassette • Set of circuit boards - $47 • 8008- $120

  32. TV-Typewriter • Radio- Electronics • September 1973 • Allowed display of alphanumeric characters on ordinary TV • ASCII based • First “Screen”

  33. 1974- Personal Computing • January: HP- 65 Programmable Calculator • Summer: Intel 8080 • July: Radio- Electronics, Mark 8 • December: Jan. issue of Popular Electronics • Altair- $400

  34. Altair • Edward Roberts – Designer • “Invented Personal Computer” • Small hobby shop, Albuquerque • 1st Personal Computer- “minicomputer kit” • 8080 Micro-processor; IC’s; TTL • Why Success?? • Promoted & designed as minicomputer • Powerful as commercial mini

  35. Altair 8800 (cont’d) • Modeled after D.G. Nova • IC memory • 1/10 cost of mini- $400 • Cost of 8080; Not $360 but $75 • Faster than Scelbi & Mark 8

  36. Altair (Cont.) Open Bus • Replaced cable after 1st model lost • Circuit boards + 2 cards • Many slots • Released specs so others made cards • But, opened door for clones • Also, company couldn’t keep up with orders • Several years to peripherals/ applications

  37. 1975-1977 • Burst of Creative Energy • User groups, newsletters, magazines, clubs, conventions, retail stores • Cassette storage; Kansas City Standard (from user group) • Lack of peripherals, storage held back the development

  38. BASIC • No OS nor programming languages for P.C. (also held back) • Current BASICs not acceptable • Versions; try to fit to small computers • Altair announcement • Bill Gates / Paul Allen decided to write BASIC for Altair • Better - available in June 1975 • Use ONLY 4K of memory • New version soon

  39. BASIC Cont. • Cost with Altair memory boards • $60 for 4K; $75 for 8K • $150 for extended (needed storage) • $500 for other 8080 systems • USR – convert to machine language • Other extensions – Peek, Poke

  40. Development of BASIC • Gates @ HARVARD; no 8080 system • With Monte Davidoff • Wrote PDP-10 using 8080 specification • 1975- Paul Allen demonstrated in Albuquerque to Roberts and Yates • Altair began to advertise

  41. Open Letter to Hobbyists • Bill Gates • Problems with illegal copies of BASIC • “The value of the computer time we have used exceeds $40,000.” • If not paid there will be no incentive to develop future software, putting personal computing at risk • Microsoft moved from N.M. to Bellevue, WA

  42. Floppy DISK • David Noble, IBM • For 370 initial control program • Didn’t expand to other uses • Gary Kildall- consultant to Intel developing languages • Noted floppy • Wrote a small program to manage information to & from floppy • Fast; Random access; read and write

  43. “Small” Operating Systems • DEC tape still heavily used on PDP’s • Late 1960’s- DEC OS/8 for PDP-8 • Showed small machines could have capabilities of mainframes • RT-11 for PDP-11- 1974 • Managed data on disks

  44. CP/M - Computer Program for Micros. • Gary Kildall (PL/M for 8080 @ IBM) • CP/M (Control Program for Micros) - $100 • To control disk drives • Similar to DEC commands • $800 with floppy drive & controller • Final piece of puzzle for PC • Formed Digital Research • Product CP/M

  45. Micros. (cont.) • IMSAI- Altair clone • Wanted CP/M license • Redesigned CP/M so small portion customized for IMSAI • Specialized Part BIOS • BASIC Input/ Output System • This Standardized system sw

  46. 1977 • All parts in place for pc revolution • Altair + add-ons • Basic + SW for money • 8 inch floppy + CP/M • Ports for peripherals • Lots of publications & groups

  47. Chapter 71972 - 1977 The Personal Computer

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