Micros that failed to make it

I have been a participant in the microcomputer world since 1976. In that time I have seen many micro architectures being rolled out and sometimes they fail to attract sufficient market share to remain viable. Here are some that I remember.

I still remember that gaudy ads in “Electronics” (once the premier magazine of the industry, from McGraw Hill) that announced the Clipper architecture from Fairchild. It was a 32-bit device in an era of 16- and 8-bit devices and found some application in workstations. It didn’t help that Fairchild was taken over by National Semiconductor in 1987 and the Clipper division was sold to Intergraph for their in-house use.

In the mid-70s there were only two CMOS microprocessors. If you wanted low-power operation you were restricted to the RCA 1802 COSMAC device (which I don’t regard as a flop) and the Intersil/Harris IM6100.The IM6100 was a 12-bit device when everything was 8 bits. As I recall it couldn’t easily fit with the 8-bit-wide devices (unlike the 16-bit devices that came later that used odd/even access to make up the 16 bits). It was designed to be compatible with the DEC PDP-8 minicomputer and even had the same instruction mnemonics. Perhaps Intersil had licensed this since Intel had already copyrighted the 8080 instruction set, forcing Zilog to create a whole new set of mnemonics for the Z80, a device that was a super-architecture of the 8080. Despite all the PDP-8 software, the IM6100 never went anywhere. When I searched for the history of the IM6100 I came across a reference from Jon Titus that there was another PDP-8 clone, the MP12 from Fabri-Tek. Apparently its legacy is the same as the IM6100.

Whilst we are dabbling in minicomputers, Data General introduced the microNova in 1977. I seem to recall it even got a mention in that wonderful book “The Soul of a New Machine” by Tracy Kidder. The microNova certainly didn’t provide a lifeline to Data General and the organization eventually failed.

The Transputer was launched with much fanfare in the early 1980s. It was aimed at the parallel computing market and even featured its own language, OCCAM, named for the 14th century English monk who is remembered for his Razor although the idea was not really his. Isn’t history wonderful? The name associated with a concept or invention is often not the actual first person to come up with it. But I digress. Despite its promise, the Transputer was also a flop.

In the 1990s, there was a move to RISC architecture and one proponent was Scenix who took a basic Microchip design, installed one peripheral (an 8-bit timer clocked by the system clock) and improved the process so that the chip (SX18, SX20, SX28) would run at up to 100MHz. The idea was that it was fast enough so that all the peripherals could be implemented in software. I must admit I bought into the philosophy until I actually completed a project. The devices were marketed by Parallax until recently discontinued, but they never really set the world on fire.

National Semiconductor tried its hand at many devices, the SC/MP (“SCAMP”), the IMP, COP and even a CMOS version of the Z80. They must have had some success, the 4-bit COP seemed to go into a lot of appliances, but when National cut its digital lines and spun out Fairchild, none of the processors survived.

When Intel brought out its 8086 16-bit family and Motorola offered the 68000, Zilog countered with the Z8000. The only thing I remember about it was that Steve Ciarcia developed a co-processor board for the IBM-PC that was described in Byte magazine. Anyone remember the Z8000 now?

Speaking of the 8086, what about the NEC V20/V30 which were supersets of the x86? That will also give us a segue into the mighty Intel’s mis-steps. Few remember that Intel invented the Digital Signal Processor, the i2920, but for some reason they never pursued that market. I am sure most of us do remember the iAPX432, the processor that ran ADA, but where is it now? The i960 was, according to Wikipedia, a success but Intel dropped marketing it “as a side effect of a settlement with DEC in which Intel received the rights to produce the StrongARM CPU.” The 960 was predeceased by the less successful i860. And for my last also-ran let us remember the MCS-96 family. It was originally developed for the automotive market and did find some success elsewhere for a while and I am not sure that it quite qualifies as a failure, but it certainly left no legacy.

It could be that some of these are still in production and that my impression is wrong. No doubt I will be corrected in the comments below. Please also add your recollections as well.

33 thoughts on “Micros that failed to make it

  1. “I do remember the Z8000. I never used one, but I read a number of articles about it.nnI did use the 1802. In fact, I still have my Cosmac ELF. from Quest Electronics. I bought and built the kit in 1978 (maybe early 79). The biggest personal downfall of

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  2. “A couple notes:nZilog also had a 32-bit Z80000 listed in a Zilog databook I once owned (but dumped a decade or so ago). Zilog puttered along with Z8 and Z80 parts until they got bought out.nnI still have my 1986 Intel databook with the iAPX432 datashe

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  3. “@TonyTibnn”Zilog also had a 32-bit Z80000 listed in a Zilog databook I once owned (but dumped a decade or so ago). “nnYou mention of the Z80000 did tickle a vague memory.nYou may remember I did a blog “Preserving Data Books From Yesteryear”nhttp

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  4. “Duanenn”I did use the 1802. “nnI cut my teeth on the 1802, based around a Popular Electronics article which I believe triggered the ELF. I actually failed to use the registers to their full extent (being self taught, and I had a rotten teacher) an o

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  5. “I first learned on COSMAC also. I do remember, though never used, the bit-slice chips. Tektronix used them, maybe in their terminals (memory of that is now fading, fast). Also remember Intel's presentation at Tek on the 4004 – almost every EE in the compa

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  6. “I only remember the AMD Am2900 bit slice family. I have the databook copied, but like you, I never actually used one. I think it may have been second sourced by Signetics. From my scans I see that Signetics had their own bit slice, the 8X02.nnWhich remi

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  7. “J just came across this e-book that covers some of the micros discussed, and some morenn”4- and 8-bit Microprocessors, Architecture and History” nnhttps://archive.org/stream/pstakem_gmail_8Bit/8-bit_djvu.txtnn”

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  8. “AubreynDuanennI also used the 1802. About a year ago I found an old hobby project that I built in 1985 using a 1802.It was built in a 6 x3 inch plastic meter box and had a 16 character LCD display. It was used to input, display and delete up to 10 mess

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  9. “Your article brings back some fond memories of devices I worked with many years ago…nnThe Zilog Z8002 (64KB address space) was big-endian, unlike the Z80. The Z8000 had a very pleasant instruction set, which was good because I programmed it in 100% a

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  10. “I still have some boards from a SCADA remote terminal adapter which used a 6809 but for some reason used some Rockwell interface chips – the 65C24 peripheral adapter and the 65C51 Comms interface adapter I think. Why they didn't stick to Motorola chips I

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  11. “I was wondering if anyone would mention the MC14500. A friend of mine was going to use one for a project but we lost touch before he finished it. A very strange chip, but it did suit some applications.”

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  12. “AAh! Peripheral chips. That takes me back to the fun days of late 70s/ early 80s when there was a new peripheral chip every week. The excitement came in seeing what unique features each one had and whether it could be interfaced to your particular micro'

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  13. “There is also the NSC32000nnI made great use of the 80c196. Personally I found it one of the nicer chips and architecture available at the time but Intel was at best ambivalent about Embedded computing. It was evident before they finally stopped product

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  14. “@RobertnnThanks for the addition. nnI see I have the data book in my scanned collection. See “Preserving Data Books From Yesteryear”nhttp://www.eetimes.com/author.asp?doc_id=1320337nn”

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  15. “I recall considering the Fairchild clipper for one project. The salesman assured me that most instructions were one clock. When pressed, he admitted the multiply took 100 clocks. I ended up using a Motorola 68020 and 68881 floating point, and also a Weite

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  16. “@Traneus (rex)nn”The 6100/PDP-8 instruction set assumed that all RAM was writable and nonvolatile. Easy with core memory, but a bear with SRAM and EPROM. I read about EPROM boards with programmable holes for SRAM. Every subroutine was self-modifying c

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  17. “I'm just now fazing out my use of the Zilog Z-180 and older Z-8 OTP in some products. The Z-180 was an improved version of the NEC 64180, which was in turn an improved Z-80. The 64180 had some instruction set issues vs the original Z-80, but the Z-180 v

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  18. “Does anybody else remember the Signetics 2650? A mid-to-late 70's vintage 8 bit device with a minicomputer-like instruction set, it had a wide variety of addressing modes, auto-increment and decrement, I/0-specific instructions and control signals, and

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  19. “RallyrnnThanks for the additions. I do remember the 64180- I seem to remember a Steve Ciarcia/Circuit Cellar article in Byte about it. NEC was not represented in South Africa and so I never was even able to consider it, even though I did work with the

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  20. “I was thinking about the MC6809, but not sure if you could say it was a flop, it went in quite a few home computers. Of course the release of the 68000 just a year or so later killed it off, a shame as it was a really nice CPU. It lasted many more years i

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  21. “The Motorola MC88000 definitely belongs in here – Motorola's first attempt at a RISC processor, I guess killed off by their involvement in the Power PC programme shortly afterwards. It was nice CPU though.nnI also played about with the AMD 27000 RISC mi

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  22. “The TMS-9995 was used in a very successful range of single-loop and dual-loop instrumentation process controllers by a company called Turnbull Control Systems later Eurotherm in the UK in the 80s and 90s(basic design was done by Mullard). We manufactured

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  23. “There was also the TI 9900 processor which I used as a research student in 1979. This was a very innovative 16-bit processor which did everything including 'register' operations in RAM memory. If you needed a context switch, you changed a memory pointer t

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  24. “Sgh798nnThanks for the additions.nn”Of course AMD got rather distracted by the PC market since then!”nnAs part of that they discontinued some fine peripheral chips like the Am9513 System Timing Controller alternately sourced by Zilog, although I a

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  25. “Chas56n”We had reels of the stuff everywhere!”nI used to use empty cotton reels I got from my mom. And then I would wind the tapes using the stand from a manual grinding wheel.nnI described my memories in a blog: “How It Was: Programming (and debug

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  26. “Yes, I do remember the Z8000. I was at General Dynamics / Fort Worth in the early 1980s, when they were doing the early F-16C/D development. Three of the four avionics computers used Z8002 processors. (The fourth used a MIL-STD-1750A processor, but I

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