Milestone-Proposal:Datapoint 2200 Personal Computer, 1970
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Docket #:2024-31
This is a draft proposal, that has not yet been submitted. To submit this proposal, click on the edit button in toolbar above, indicated by an icon displaying a pencil on paper. At the bottom of the form, check the box that says "Submit this proposal to the IEEE History Committee for review. Only check this when the proposal is finished" and save the page.
To the proposer’s knowledge, is this achievement subject to litigation? No
Is the achievement you are proposing more than 25 years old? Yes
Is the achievement you are proposing within IEEE’s designated fields as defined by IEEE Bylaw I-104.11, namely: Engineering, Computer Sciences and Information Technology, Physical Sciences, Biological and Medical Sciences, Mathematics, Technical Communications, Education, Management, and Law and Policy. Yes
Did the achievement provide a meaningful benefit for humanity? Yes
Was it of at least regional importance? Yes
Has an IEEE Organizational Unit agreed to pay for the milestone plaque(s)? Yes
Has the IEEE Section(s) in which the plaque(s) will be located agreed to arrange the dedication ceremony? Yes
Has the IEEE Section in which the milestone is located agreed to take responsibility for the plaque after it is dedicated? Yes
Has the owner of the site agreed to have it designated as an IEEE Milestone? Yes
Year or range of years in which the achievement occurred:
1969-1971
Title of the proposed milestone:
Datapoint 2200 Personal Computer, 1970
Plaque citation summarizing the achievement and its significance; if personal name(s) are included, such name(s) must follow the achievement itself in the citation wording: Text absolutely limited by plaque dimensions to 70 words; 60 is preferable for aesthetic reasons.
This plaque recognizes the technological advances of the Datapoint 2200, the first desktop personal computer, designed in 1969 and produced by Computer Terminal Corporation. The Datapoint 2200 pioneered the computer architecture and instruction set that became the basis for the Intel 8008 and many other microprocessors.
200-250 word abstract describing the significance of the technical achievement being proposed, the person(s) involved, historical context, humanitarian and social impact, as well as any possible controversies the advocate might need to review.
The Datapoint 2200 was the first mass produced, self-contained, desktop computer intended to be used by a person one-on-one and in real-time. Before 1970 users either interacted with a mainframe computer or used a terminal connected to a time share system. In order to obtain a desktop footprint with fully integrated hardware, the Datapoint 2200 introduced a number of technical innovations including the first use of solid state memory and a switching power supply in a commercial production computer. The Datapoint 2200 introduced concepts that formed the basis for the architecture of following generations of personal computers. These include 8 bit words, the minimalist instruction set which became the basis of Intel 8008 and 8080 processor chips, the use of cassette tape memory, and a parallel data bus for communicating with peripheral devices.
IEEE technical societies and technical councils within whose fields of interest the Milestone proposal resides.
Computer Society Power and Energy Society (Switching Power Supply)
In what IEEE section(s) does it reside?
Lone Star Section
IEEE Organizational Unit(s) which have agreed to sponsor the Milestone:
IEEE Organizational Unit(s) paying for milestone plaque(s):
Unit: Lone Star Section
Senior Officer Name: Walt Downing
IEEE Organizational Unit(s) arranging the dedication ceremony:
Unit: Lone Star Section Life Members Affinity Group
Senior Officer Name: Warren Conner
IEEE section(s) monitoring the plaque(s):
IEEE Section: Lone Star Section
IEEE Section Chair name: Walt Downing
Milestone proposer(s):
Proposer name: Ernest Franke
Proposer email: Proposer's email masked to public
Proposer name: Michael Fischer
Proposer email: Proposer's email masked to public
Please note: your email address and contact information will be masked on the website for privacy reasons. Only IEEE History Center Staff will be able to view the email address.
Street address(es) and GPS coordinates in decimal form of the intended milestone plaque site(s):
Street Address: San Antonio Museum of Science and Technology, 102 Mabry Drive, San Antonio, TX, 78226
GPS Coordinates: 29.381788, -98.569224
Describe briefly the intended site(s) of the milestone plaque(s). The intended site(s) must have a direct connection with the achievement (e.g. where developed, invented, tested, demonstrated, installed, or operated, etc.). A museum where a device or example of the technology is displayed, or the university where the inventor studied, are not, in themselves, sufficient connection for a milestone plaque.
Please give the address(es) of the plaque site(s) (GPS coordinates if you have them). Also please give the details of the mounting, i.e. on the outside of the building, in the ground floor entrance hall, on a plinth on the grounds, etc. If visitors to the plaque site will need to go through security, or make an appointment, please give the contact information visitors will need. The San Antonio Museum of Science and Technology (SAMSAT) has a close relationship to the history of the Computer Terminal Corporation (CTC) and the development of the Datapoint 2200. The design of the 2200 took place at several CTC offices and labs (and even employee residences) in San Antonio several miles from the museum. After CTC was renamed Datapoint Corporation and ultimately began experiencing financial difficulties, a number of CTC employees (notably David Monroe) began collecting design documents, early prototypes and other items related to the 2200. These items formed the nucleus of the SAMSAT Datapoint display concerning the history of the personal computer which has become the largest collection of Datapoint artifacts in the world. SAMSAT now operates the Datapoint Archive with a mission to preserve the history of the Datapoint Corporation and products. In addition, SAMSAT is a focal point for Datapoint ex-employees and hosts an annual Datapoint reunion.
SAMSAT is located on the Tech Port San Antonio campus, City of San Antonio. Tech Port San Antonio is the largest industrial park in Bexar County, Texas and is on the 1900 acre site of the historic Kelly Air Force Base. Tech Port San Antonio is a political subdivision of the state of Texas and the buildings on the site are owned by the Port. There are over 80 corporations operating from the Port in over 10 million square feet of industrial and office space. The are other historical markers at Port San Antonio celebrating the history of aviation and the Air Force including retired Air Force airplanes on monuments.
Are the original buildings extant?
The Datapoint 2200 (hereafter referred to simply as “the 2200”) was designed and put into production at the Datapoint headquarters building, 9725 Datapoint Drive in San Antonio. This building is still in place but it has been remodeled and currently houses the School of Optometry of The Incarnate Word University. The current use and operations of this building have no association with Datapoint or the development of the 2200. As discussed above, The SAMSAT building at PortSA is a much more suitable location for the plaque.
Details of the plaque mounting:
It is proposed that the mounting would be in the entrance lobby of the SAMSAT building
How is the site protected/secured, and in what ways is it accessible to the public?
The intended plaque would be in the entrance lobby of the SAMSAT museum. This area is accessible to the public at any time the museum is open but is securely locked at other times. No prior appointment or arrangement would be needed to visit the site. It is a well-lighted area and is monitored by several surveillance cameras. The general area currently has drive-by patrol by the San Antonio Police department units assigned to Port San Antonio, a Port San Antonio private patrol service, and Air Force police are in the area.
Who is the present owner of the site(s)?
Port Authority, City of San Antonio 907 Billy Mitchell Blvd. San Antonio, TX 78226-1802
What is the historical significance of the work (its technological, scientific, or social importance)? If personal names are included in citation, include detailed support at the end of this section preceded by "Justification for Inclusion of Name(s)". (see section 6 of Milestone Guidelines)
The story of the 2200 begins with the need for computer terminals to support timeshare computer systems. During the late 1960’s there were over a hundred timeshare computer companies offering services to major banks, oil companies, pharmaceutical companies, manufacturers and others. All of these required dozens of computer terminals, typically Teletype ASR-33 or IBM 2471 mechanical teletypewriters which were slow, noisy and required significant maintenance.
On July 6, 1968 Gus Roche and Phil Ray incorporated the Computer Terminal Corporation. Their business plan was to design and produce “glass-Teletype” all-electronic computer terminals with a CRT display that would be compatible with the Teletype Corporation ASR-33. They named their terminal the Datapoint 3300 because they claimed that it was “100 times better” than its mechanical predecessor the ASR-33. The first Datapoint 3300’s were shown at the 1969 Spring Joint Computer Conference in Boston. (Both the Spring Joint Computer Conferences and the Fall Joint Computer Conferences were sponsored by the American Federation of Information Processing Societies. The IEEE was one of the founding members of AFIPS) The 3300 terminals were very well received at the Conference and by September 1969 nearly 1500 units were on order.
Many customers requested custom modifications which were difficult and time-consuming to do in the hardware implementation of the 3300. In order to meet these requests and to broaden the market, CTC decided to produce a programmable device. Over Thanksgiving in 1969, Harry Pyle and Victor Poor specified basic architecture and an instruction set of the new computer. The minimalist design used eight registers (8 bits each), and all arithmetic and logical operations were done in serial.
The2200 introduced several significant technological advances that were incorporated into later personal computers. As microprocessors did not yet exist, and because minicomputer architectures were too logic intensive to fit in the desktop machine and would have consumed too much power, a new processor architecture was required. This architecture included:
a. 8 bit words/registers – Minicomputers of the late 1960’s typically used 12 bit (DEC PDP-8) or 16 bit (Data General Nova) words for instructions, addresses and data. To reduce the bus width, use less memory, and conserve power reducing the power supply size, the 2200 used 8 bit words and combined two to obtain a 16 bit address space.
b. Minimalist instruction set with register-register operations – The designers implemented as many instructions as were needed, but no more, to reduce the logic required to decode and execute the instruction. The Datapoint 2000 Version 1 had 31 basic instructions in its instruction set. Many of the basic instructions included modifiers (such as immediate or conditional execution) so the total number of implemented operation codes (and the programming capability) was larger.
c. “little-endian” number representation – Most historical and mainframe computers used big-endian number representation for arithmetic with the most significant byte of a word stored at the lowest numbered memory address. Since the Datapoint 2200 used bit serial processing, big-endian representation would have made it very difficult to propagate carrys during arithmetic operations. This problem was solved by using little-endian representation and arithmetic processing. This convention was carried over to the Intel 8008 and the following 8086 and x86 processors.
d. Memory – Minicomputers in 1969 were all using core memory for main memory. Core memory was too large and too expensive for a personal desktop computer, so an alternative was needed. RAM memories had not yet become available in sizes larger than 64 bytes, and were bipolar devices and power hungry, so that wasn’t an option. However serial MOS memories were becoming available. 128 bit Electronic Arrays chips were selected for the prototypes, and 256 bit Intel chips were used in production. Interestingly, both Intel and CTC were founded in 1968 and CTC was Intel’s primary customer for many years. The same Intel shift registers were used for the CRT display refresh in the 3300 and 2200, and for the processor main memory in the 2200 Version 1.
e. Serial Bus and ALU Architecture – The 2200 Version 1 was implemented with a serial one-bit data-path and logic in the ALU to minimize gate count so the processor would be as small as possible and use minimum power. The processor was implemented with SSI logic with a minimum of MSI logic as there were few MSI parts available in 1969.
f. External I/O channel – There was a requirement for future external I/O devices such as an external Selectric typewriter printer (the first printer supporte d for 2200 word processing), disk drives and the like. But the RS-232 communications bus almost universally used for minicomputers and terminals in 1969 was not fast enough for some of these peripherals. CTC designed a new 8 bit “high speed” parallel bus with embedded power to support these devices.
The Datapoint 2200 also introduced tape cassette data storage. Minicomputers used multi-track data tape storage which required large read/write heads and wide tape. In order to save space and expense, audio cassettes from consumer Norelco tape drives were modified to add solenoid controls to enable audio cassettes to be used for removable mass storage. The operating system that was developed for the early 2200 was CTOS (Cassette Tape Operating System). It was later expanded to become DOS (Disk Operating System) to run Diablo and several subsequent other disk drives and floppy drives when they became available. Other software applications included terminal emulators, a text editor, an assembler, an assortment of primitive computer games, a desk calculator emulator, a business language of Datapoint’s design called Databus, Basic, and others.
One requirement for the new computer was that it should be a desktop device, occupying the footprint of an IBM Selectric® typewriter (18.5” wide and 9.6” deep). This space constraint led CTC to work with Intel and TI in an effort to implement the system on a single integrated circuit. Neither Intel nor TI were able to produce a chip soon enough to meet the CTC production schedule and the 2200 was implemented with TTL logic chips.
The 2200 was shown in April, 1970 and at the 1970 Fall Joint Computer Conference in Houston. The first sale was to General Mills on May 25, 1970. Early users included Pillsbury who used it for payroll calculations and Levi Strauss for data entry applications. Others were used by order-entry firms and insurance companies. Due to this success, CTC proceeded with development of the 2200 Version II which was about 100 times faster than the original while maintaining comparability to run all existing software that had been developed for the 2200.
Later both Texas Instruments, with the TMX 1795, and Intel completed the single chip implementations. The Intel chip was initially called the “SPD 1” (Semiconductor Processor Development 1), when delivered, was called the “1201” (12 for custom, 01 for the first custom Intel chip), and later changed to “8008” when in volume production. The TI chip was a chip set with memory, and the memory chip proved not to be reliable. In any case, these were the first production 8-bit microprocessor chips and both were based on the CTC architecture and implemented the identical instruction set to the CTC Version 1 2200.
In summary, the Datapoint 2200 was the first mass produced, self-contained, desktop computer intended to be used by a person one-on-one and in real-time.
What obstacles (technical, political, geographic) needed to be overcome?
The primary obstacles faced during development of the 2200 were technical issues related to the need to keep the computer small, easy to use and self-contained. Prior to development of the 2200, computers were large mainframes running batch or timeshare applications or rack-mounted minicomputers requiring additional peripherals for input, output and other uses. Multiple innovations were needed to achieve a self-contained, desktop computer.
1. Industrial Design – the Datapoint 2200 was designed as a desktop machine that would fit on a small desk or a typewriter stand. Because it was considered of paramount importance that the machine would be at home in commercial and residential settings, a world-class industrial design firm, Raymond Lowey and Associates of New York, was hired to study human factors and produce a user-friendly packaging design. The IBM Selectric® typewriter represented the state-of-the-art typewriter in 1969 and was used as a design benchmark for the new computer design. For example, the shape of the key-caps was patterned after the IBM Selectric, and the footprint and the height of the personal computer package were similar. The resulting design went on to be displayed at the Museum of Modern Art acknowledging the 2200’s revolutionary human factors and design. This small packaging size was an extreme engineering challenge in 1969 because a terminal (keyboard and display), processor and memory, mass storage, I/O channel and power supply had to be integrated in a very compact space.
2. N-Key Rollover – Minicomputers and timeshare machines initially used Teletype machines for I/O. Typical data entry into these computers did not require high typing speeds, and the Teletype machines that were used did not have multi-key rollover. In the office and home typewriter market, however, the popular IBM Selectric provided n-key rollover to allow persons to type at high speeds for document creation. In order to preserve this feature and allow persons to type documents at high speeds, CTC designed special capacitor-coupled diode-array ROM for the keyboard to provide n-key rollover as in the Selectric.
3. Eighty Character Display - The CRT display had to present 80 characters horizontally to provide enough characters for word processing and other applications. This was beyond the bandwidth of normal NTSC television monitor technology which supported only 40 characters, so CTC used their patented “diddle-scan” technique to sweep the CRT. The CRT also had to be custom tooled to reduce its height to fit in the desired Selectric-like size profile.
4. Switching power supply – Prior to 1970 all computers used linear regulated, 50/60 Hz transformer-based power supplies. A linear power supply would have been too heavy and bulky for the small self-contained, desktop computer Datapoint was developing, so engineers designed a switching power supply. This was the first use of a switching power supply in a commercial computer. Prior to this, the Apollo Guidance Computer had used switching power supplies. The 2200 switching supply had to operate from 120 VAC power mains which was much more difficult from operation on the 28 VDC bus of the Apollo spacecraft. The higher voltages of the 120 VAC mains (and later 240 VAC) plus the transients seen on the mains from other switched inductive loads made this switcher design a novel and very difficult task, particularly in light of the voltage ratings of transistors available in 1969.
5. Smaller and less expensive memory – In 1969, mainframe and minicomputers used magnetic cores for main memory, but core memory would have been too large and expensive to meet the design goals of the 2200. Solid state RAM beyond 64 bits was not available in 1969 so the computer memory was implemented with serial recirculating memory composed of 256 bit (in the prototypes), and 512 bit (in production) shift-register chips.
What features set this work apart from similar achievements?
Prior to the 2200, the smallest computers were minicomputers that utilized awkward switch registers, register lamps and a bootstrap loader which loaded the operating system from paper tape or 9 track tape. These mini-computers were typically 19” relay rack-mounted, were modular in concept with external storage devices and displays, and did not feature office or personal applications.
The Datapoint 2200 was the first of a breed of computers that were designed not for engineers to use, but for ordinary people. The small size of the machine was seen as of paramount importance so that it would not intimidate a user and could easily fit on a small desktop or even a typewriter stand in a home or office.
Why was the achievement successful and impactful?
The Datapoint 2200 was very innovative and successful as evidenced by the sale of ______ units in the first year. Prior to 1970 commercial computers were either mainframe systems used for scientific computing and batch processing or time share systems composed of terminals connected to a remote computer. The 2200 was the first desktop personal computer with fully integrated hardware intended to be used by a single person. It included a number of “firsts” in order to provide this computing capability in a desktop footprint including first commercial production computer to use solid state memory and first commercial computer to use a switching power supply.
Datapoint 2200 systems included a suite of generalized software including; an operating system (CTOS), terminal emulators, a text editor, languages (assembly, Basic and Databus) and some games. The system provided an attractive cost/performance point which led to its use in university settings as well as businesses.
Supporting texts and citations to establish the dates, location, and importance of the achievement: Minimum of five (5), but as many as needed to support the milestone, such as patents, contemporary newspaper articles, journal articles, or chapters in scholarly books. 'Scholarly' is defined as peer-reviewed, with references, and published. You must supply the texts or excerpts themselves, not just the references. At least one of the references must be from a scholarly book or journal article. All supporting materials must be in English, or accompanied by an English translation.
1. Wood, Lamont (2013). “Datapoint: The Lost Story of the Texans Who Invented the Personal Computer”. Hugo House Publishers, Ltd. ISBN 9781936449361
2. Wikipedia entry on Datapoint 2200: https://en.wikipedia.org/wiki/Datapoint_2200 (PDF file attached) 3. Wood, Lamont. “Forgotten PC History: The true origins of the personal computer”, Computerworld, August 8, 2008. 4. Computer Terminal Corporation “1970 Annual Report”, David Monroe collection, (PDF attached) 5. Datapoint 2200 Reference Manual, David Monroe collection, (PDF attached) 6. Photo of prototype 2200 showing circuit boards. SAMSAT collection photo by Joe Jankowski 7. U.S. patent number 3,706,905, granted by the patent office on 1972-12-19 for the CRT deflection compensation system. (PDF attached) 8. U.S. design patent number 2234,415, granted by the patent office on 1972-07-25 for the Datapoint 2200 (PDF attached) 9. Shirriff, Ken (2016); “The Surprising Story of the First Microprocessors”, IEEE Spectrum, August 30, 2016, pp 48-54
[We don’t need to use all of the following. Probably only the 6 or 8 most significant should be included]
Many of the following documents provide evidence of events and dates in the development and deployment of the Datapoint 2200. Most of these documents are in the personal records of Dr. Earl Schweppe, David Monroe and David Gust. The originals are available in the SAMSAT History Archive.
i. CTC concept plan ii. CTC business plan iii. Financing document to fund 2200 production, Oct/Nov 1969 iv. Harry’s architecture drawings v. Intel 1201 processor proposal 3/4/1970 vi. CTC PO to Intel for the 1201 3/18/1970 vii. TI 2200 chip proposal 6/23/1970 (incomplete document) viii. 2200 Design Patent Filed 11/1970 ix. Demos: 1. Pillsbury demo Dave Gust (need date)
2. University of Kansas demo Dave Gust to Schweppe and Monroe (need date)
x. 2200 announcements 1. “Banker’s Show” – haven’t found this as of yet 2. Datamation Article 3. Research other Computer Journals T.B.D. xi. 2200 product brochures xii. 2200 V1 reference manual xiii. CTOS listing with early date xiv. Debug program listing – do we have it?– what is the date? xv. 2200 hardware price list xvi. 2200 software list xvii. Schweppe KU purchase Justification Letters xviii. PO from University of Kansas xix. First Installation Report xx. Schweppe References to “Personal Computer’ 1. Letter to Robert W. Rector UCLA 11/20/1971 xxi. Computer World 8/8/1977 Adam Osborne“ Datapoint 2200 CPU is the grandfather of today’s microprocessor…”
Supporting materials (supported formats: GIF, JPEG, PNG, PDF, DOC): All supporting materials must be in English, or if not in English, accompanied by an English translation. You must supply the texts or excerpts themselves, not just the references. For documents that are copyright-encumbered, or which you do not have rights to post, email the documents themselves to ieee-history@ieee.org. Please see the Milestone Program Guidelines for more information.
Please email a jpeg or PDF a letter in English, or with English translation, from the site owner(s) giving permission to place IEEE milestone plaque on the property, and a letter (or forwarded email) from the appropriate Section Chair supporting the Milestone application to ieee-history@ieee.org with the subject line "Attention: Milestone Administrator." Note that there are multiple texts of the letter depending on whether an IEEE organizational unit other than the section will be paying for the plaque(s).
Please recommend reviewers by emailing their names and email addresses to ieee-history@ieee.org. Please include the docket number and brief title of your proposal in the subject line of all emails.
