Tuesday, October 20, 2020

Intel 8008 Microprocessor began as a 'Computer Terminal Corporation 2200" - an Electronic Data Terminal

This is a poplar post and I updated it and reposted it. David Larsen
The first 8 bit Intel microprocessor -the 8008 was the result of designing the Computer Terminal Corporation "CTC 2200" logic into a single chip.  The CTC2200 was a successful project to design an electronic version of the 'workhorse' Teletype data terminal  of the 60/70s  - the Teletype was an all mechanical  communications terminal with hundreds of gears and levers. .  CTC contracted  Intel to design a microprocessor however the process was slow and CTC did not  use the design.The result was Intel had its first 8 bit microprocessor (8008).  See short story about the interesting origin of the 8008 at the end of this post.

We are fortunate to have this CTC 2200 in our computer collection and on display in the museum.

See video of this computer "CLICK"

  CLICK photo to enlarge
CTC2200 data terminal
CTC2200 data terminal 

CTC's TTL-based desktop personal computer, called the Datapoint 2200, was unveiled in 1970, with cassette tapes for 130KB of mass storage and 8K of internal memory.

The first end user sale was to a chicken farmer in the South who programmed the CTC2200 to write payroll checks. So I you could say a chicken farmer was the first  user of a programmable microcomputer.

Bugbook Historical Microcomputer Museum
CTC 2200 with case removed

The CTC 2200 is densely packed with Small Scale Integrated circuits and other parts. The mechanical design seems to be well done and the unit is solid and sturdy. ( also very heavy )

CTC2200 keyboard
CTC2200 keyboard

The design includes about 100 small scale integrated circuits along with discrete components- transistors - resistors -diodes and capacitors. In this photo you can see 4 printed circuit boards under the display and in back of the keyboard.  Their are 4 printed circuit boards under the tape deck area and 4 memory boards next to the CRT display.

CTC2200 back panel heat sink
CTC2200 back panel heat sink 

The unit was designed to fit in the same area as an IBM Selectric Typewriter. This did not give much room and the unit is packed with cards and circuits.

Here you see the large heat sink on the back of the terminal. It is heavy and weighs about 40 lbs.

CTC2200 memory cards
CTC2200 memory cards

The 4 memory cards each contain 4Kb of RAM for a total of 16 Kb. The CTC2200 machines with 16Kb sold for $16,000.

CTC2200 cassette tape decks
CTC2200 cassette tape decks

The unit had  2 read-write cassette decks for 130KB of mass storage.

CTC2200 CRT HV and driver circuits
CTC2200 CRT HV and driver circuits

A view of the high voltage for the CRT and Memory area.

CTC2200 serial # 498 on PC board
CTC2200 serial # 498 on PC board 

The only serial number I have found so far is 498 on the corner of this card.

Here is some great research about the first microprocessor - Ken Shirriff's Blog 

Short story about the origin of the Intel 8008 microprocessor.

The Teletype was the communications terminal used from the late 50's until in the 80s - first as a data  terminal connected to the telephone system with a modem. It was used to send messages to users and mostly for sending and receiving telegrams. Later the Teletype was used for a minicomputer printer and paper tape punch to store the data.  Long distant voice calling  were so expensive and unreliable it was rarely used  in the 50's and 60s'.

The Teletype was a totally mechanical device that could decode 8 bit data strings - ASCII code - and print all capital letters on paper & also punch paper tape for permanent Storage of the data. The Teletype could also read the paper tape and convert the code into the 8 bit serial ASCII data for transmitting over a telephone line using a modem. The word Byte for 8 bits of data most likely came from this sending and receiving alphabetic characters as 8 bits of data.  
                                                                                                                                                                                                                                                                 CLICK photo to enlarge
ASR 33 Teletype
The Teletype was a great invention however it was a mechanical monster with 100's of cams and levers that could and failed often. It was a mechanical device and very noisy & distracting in and office.

In the end of 1960's, 2 graduates at Case Western Reserve University in Ohio, Harry Pyle and Victor D. Poor, came up with the idea of a high density integrated circuit which would be programmable. Harry and Victors ideas were used to create the logic of the CTC2200 and this became the code for the 8008 microprocessor. When transistors and more importantly integrated circuits became available and all electronic version of the Teletype became possible.

The Computer  Terminal Corporation produced an electronic replacement for the Teletype the "CTC 2200". The CTC 2200 was actually programmable terminal using a custom designed 8 bit computer. The computer was made from discrete components and and small scale integrated  circuits. Microprocessors had not been  designed in the late 60's when the CTC2200 was developed.

The engineers at CTC did have the idea to put the computer logic they had designed into the CTC2200 on a single chip  - making a microprocessor.  A design team went to Intel to have them design and make a microprocessor  using the logic in the CTC2200. Robert Noyce of Intel when approached with this project did not like the idea as he thought a computer on a chip would hurt the memory chip market of Intel by competing with computer makers using the Intel memory chips.  However Robert Noyce did agree to make the chip for $50,000.

The CTC engineers also went to Texas Instruments and ask them to make the same chip to be sure they had a backup source.  The Texas Instrument chip did not function properly and was not used. The Intel chip was a long time in development. The CTC team decided to just build the 2200 terminal with there current design of about 100 small scale integrated circuits and give up the rights to the intellectual property rights for the   Intel microprocessor design --and did not pay the $50,000 to Intel.  Giving up the intellectual rights to the microprocessor is among the worst business decisions ever.

Intel went ahead with the full development of the microprocessor and called it the 8008. The microprocessor used the same digital logic and operational software codes as CTC2200 .

The computer logic in the CTC2200 then was an original 8 bit computer that used the 8008 software code and was  the beginning  of 8 bit computers (8008 microprocessor) for Intel.

Here are some links to more complete stories of the CTC2200 / Intel story. Some of the information I used came from these references.
Computer World 
History of Computers
San Antonio "Express-News"

Their is a lot more to this very interesting story of how the first Intel 8 bit 8008 microprocessor came about - here is the REST of the STORY 

David G Larsen
I  remember for many years I did not think I would find a CTC2200 and wanted to have one for it is one of the first programmable microcomputers. During the late 80's I was able to find not only this fine example and the source also had a  model the CTC1100. The CTC 2200 and 1100 now are part of the "Bugbook Historical Microcomputer Collection"

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