Micro Instrumentation and Telemetry Systems: Difference between revisions

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Owners of mainframe systems and minicomputers could purchase additional memory, interface boards and peripherals from third party suppliers; so it was predictable that owners of the Altair 8800 computer would do the same. MITS's delays in delivery of systems and accessories accelerated the formation of Altair compatible suppliers. The first ones started appearing in mid-1975 and by July 1976 complete computers systems were readily available.<ref name = "Byte July 1976">{{cite journal | journal = Byte | volume = 1 | issue = 11 | title= Advertisements | publisher = Byte Publications | ___location = Peterborough NH | date = July 1976}} Numerous advertisers in the issue claim Altair compatibility.</ref> The technical manuals for the Altair 8800 provided electrical schematics of the 100 pin computer bus allowing others to design compatible boards. There was not a proper technical standard at the time and some "compatible" boards did not work with other "compatible" boards. Later, the industry developed the [[S-100 bus]] standard.<ref name = "S100 Bus">{{cite journal | last = Morrow | first = George | authorlink = George Morrow (computers) |author2=Howard Fullmer | title = Microsystems Proposed Standard for the S-100 Bus Preliminary Specification, IEEE Task 696.1/D2 | journal = Computer | volume = 11 | issue = 5 | pages = 84–90 | publisher = IEEE | date = May 1978 | doi = 10.1109/C-M.1978.218190}}</ref>

[[Bill Godbout]] Electronics in Oakland, CA was the parts supplier to many of the hobbyists and students from [[University of California, Berkeley|Berkeley]]. [[George Morrow (computers)|George Morrow]] approached Godbout with several Altair compatible designs that Godbout agreed to produce and sell.<ref name = "George Morrow 1979">{{cite journal | last = Williams | first = Tom | title = Hazards & Opportunities in the Micro Market: Interview with Thinker Toy's George Morrow | journal = Intelligent Machines Journal | volume = 1 | issue = 3 | page =2 | date = February 14, 1979 | url = https://books.google.com/books?id=Ez4EAAAAMBAJ&pg=PA2 | issn = 0199-6649 | publisher = InfoWorld Media Group, Inc.}}</ref><ref name = "Altair clones">{{cite book | last1 = Freiberger | authorlink1 = Paul Freiberger | first1 = Paul | first2 = Michael | last2 = Swaine | authorlink2 = Michael Swaine (technical author) | title = Fire in the Valley | publisher = McGraw-Hill | year = 2000 | edition = 2nd | pages = [https://archive.org/details/fireinvalleymaki00frei_0/page/123 123–129] | isbn = 0-07-135892-7 | url = https://archive.org/details/fireinvalleymaki00frei_0/page/123 }}</ref> The October 1975 Byte magazine carried an advertisement headlining "Get your MITTS on a Godbout RAM kit." <!-- The ad actuality use "MITtS" --> The 4K byte Altair compatible board was $131.07.

Godbout also sold components to [[Processor Technology]] for their 4K Static RAM board and serial / parallel interface board. [[Lee Felsenstein]] designed an Altair compatible video board that provided 16 lines of 64 upper and lower case characters on a black and white television. This $160 board became very popular and led to the Processor Technology Sol-20 Computer in 1976.<ref name = "VDM-1">{{cite magazine | date = February 1976 | title = Introducing VDM-1|magazine= Popular Electronics | volume = 9 | issue = 2 | page =100}} Processor Technology Video Display advertisement. Features 16 lines, 64 characters, upper and lower case. $160</ref>

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In December 1974 Bill Gates was a student at [[Harvard University]] and Paul Allen worked for [[Honeywell]] in Boston. They saw the Altair 8800 computer in the January 1975 issue of ''Popular Electronics'' and knew it was powerful enough to support a [[BASIC]] interpreter.<ref>The January 1975 issue of ''Popular Electronics'' was published on November 29, 1974. [[:File:Copyright Popular Electronics 1975.jpg|Copyright record.]]</ref> They wanted to be the first to offer BASIC for the Altair computer, and the software development tools they had previously created for their [[Intel 8008]] microprocessor based [[Traf-O-Data]] computer would give them a head start.<ref>Manes (1994), 68–70.</ref> While their friend, Paul Gilbert, was building the computer, Allen wrote a program that ran on a DEC [[PDP-10]] [[time-sharing]] computer that simulated the 8008 system. He also modified DEC's [[Assembly language|macro assembler]] to produce the machine code for the 8008 microprocessor. The Traf-O-Data software could be written and debugged before the computer hardware was complete.<ref>Manes (1994), 50–54. Gates and Allen worked at TRW where they had unlimited access to a PDP-10.</ref>

Harvard had a [[Digital Equipment Corporation|DEC]] [[PDP-10]] that was available for student use. They would use it to develop BASIC.<ref name="harddrive PDP-10">{{cite book | last=Wallace | first =James | author2=Jim Erickson | title=Hard Drive: Bill Gates and the Making of the Microsoft Empire | publisher=John Wiley & Sons | year=1992 | pages=[https://archive.org/details/harddrivebillgat00wall_0/page/81 81–83] | isbn =0-471-56886-4 | url=https://archive.org/details/harddrivebillgat00wall_0/page/81 }}"When Harvard officials found out that he (Gates) and Allen had been making extensive use of the university's PDP-10 to develop a commercial product, they were not pleased." The computer was funded by the Department of Defense and was under the control of Professor Thomas Cheatham. "Although DARPA was funding the PDP-10 at Harvard, there was no written policy regarding its use."</ref> While Allen modified their development software for the new 8080 microprocessor, Gates began writing 8080 assembly language by hand on yellow legal pads. They enlisted another Harvard student, [[Monte Davidoff]], to write the math routines.<ref>Manes (1994), 50–54.</ref>

By early February the program coding switched from legal pads to the PDP-10 and a preliminary version was completed by March 1975.<ref>Manes (1994), 71. "A much later version of the source code memorializes the date as February 9, 1975, but the project almost certainly began earlier - during Harvard's January 'reading period' …" [[:File:Altair Basic Sign.jpg|Source code display in museum]]</ref> Gates and Allen had been in contact with Roberts and MITS and the older looking Paul Allen would travel to Albuquerque in March. MITS needed more time to get a computer with 7k bytes of memory working, and they needed more time to get the software finished. When Allen arrived at MITS it took a day to get the software running; Allen remembers this being caused by computer memory problems<ref>Manes (1993), 75.</ref> while Roberts remembers the delay was due to software problems.<ref>Young (1998), 163.</ref>

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== Works cited ==

*{{cite book | last = Ceruzzi | first = Paul E. | title = A History of Modern Computing | publisher = MIT Press | year = 2003 | ___location = Cambridge, MA | isbn = 0-262-53203-4 | url = https://archive.org/details/historyofmodernc00ceru_0 }}

*{{cite book | last = Manes | first = Stephen | authorlink = Stephen Manes |author2=Paul Andrews | title = Gates | publisher = Simon and Schuster | year = 1994 | ___location =New York | isbn = 978-0-671-88074-3}}

*{{cite book | last = Mims | first = Forrest M | authorlink = Forrest Mims | title = Siliconnections: Coming of Age in the Electronic Era | publisher = McGraw-Hill | year = 1986 | ___location = New York | isbn = 978-0-07-042411-1 | url = https://archive.org/details/siliconnectionsc00mims }}

*{{cite book | last = Roberts | first = H. Edward | authorlink = Ed Roberts (computer engineer) |author2=Forrest Mims | title = Electronic Calculators | publisher = Howard W Sams | year =1974 | ___location = Indianapolis | isbn = 978-0-672-21039-6}}

*{{cite book | last = Young | first = Jeffrey S. | title = Forbes Greatest Technology Stories: Inspiring Tales of the Entrepreneurs | publisher = John Wiley & Sons | year =1998 | ___location =New York | isbn = 0-471-24374-4}} Chapter 6 "Mechanics: Kits & Microcomputers"