IBM 5 bit microcontroller

By: Adrian (, July 24, 2022 9:53 pm
Room: Moderated Discussions
Duane Sand ( on July 24, 2022 11:50 am wrote:
> A friend worked in cpu engineering at IBM in the early 80's. He recalls that there was a very fast microcontroller
> known as "the 5 bit engine" that ran its instructions several times faster than the contemporary 3033 and
> 3081 370-range mainframes it was used with. It was used as the microprogram core of the desk-sized IBM
> 3060 operator and maintenance console of the 3033. Its speed apparently caused as much of a stir among
> IBM engineers as the 801 risc project. Google does not find much about this speed demon. On comp.arch
> in 1999, Julian Thomas responded to Del Cecchi's comment about IBM microcontrollers with
> "Then there was the infamous 5 bit engine used in the 303x consoles!"
> My friend recalls this engine as having a 7nsec instruction time. And that engineering teams
> resisted using its approach to build fast microcoded 370's instead of lots of hardware.
> What was this amazing thing? How was it so fast? How was it used? Did it need water cooling,
> also? What were the reasons to not use similar techniques for the mainframes themselves? Could
> a similar design be used in our latest cmos chips, with similarly fast single-thread results?

I believe that the "3060" name for that console might be wrong, as googling for it finds a much older IBM 3060 console, which was used in 1970 for IBM 370.

At bitsavers, there are a couple of manuals from 1979 for IBM 3033, which describe the console "IBM 3036", which appears to be that meant by you.

Unfortunately, while those manuals give a detailed description of the external behavior of the IBM 3036 console, they do not give any information about how its microcoded processor is implemented.

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TopicPosted ByDate
IBM 5 bit microcontrollerDuane Sand2022/07/24 11:50 AM
  IBM 5 bit microcontrollerAdrian2022/07/24 09:53 PM
    IBM 5 bit microcontrollerAdrian2022/07/24 10:07 PM
      IBM 5 bit microcontrollerDuane Sand2022/07/24 11:39 PM
        IBM 5 bit microcontrollerAdrian2022/07/25 12:39 AM
  IBM 5 bit microcontrollerMatt Sayler2022/07/26 11:57 AM
    IBM 5 bit microcontrollerDuane Sand2022/07/26 03:19 PM
      IBM 5 bit microcontrollerMark Roulo2022/07/26 05:44 PM
        IBM 5 bit microcontrollerPaul Bishop2022/07/27 02:48 PM
          IBM 5 bit microcontrollerPaul Bishop2022/07/27 03:32 PM
            IBM 5 bit microcontrollerDuane Sand2022/07/28 01:44 AM
              IBM 5 bit microcontrollerPaul Bishop2022/07/28 12:45 PM
                IBM 5 bit microcontrollerDuane Sand2022/07/30 03:44 PM
                  IBM 5 bit microcontrollerPaul Bishop2022/07/31 04:03 AM
                    IBM 5 bit microcontrollerDuane Sand2022/07/31 10:26 AM
                      IBM 5 bit microcontrollerPaul Bishop2022/07/31 04:08 PM
                        IBM 5 bit microcontrollerDuane Sand2022/08/01 01:20 AM
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