> On May 4, 2025, at 5:51 PM, Will Cooke via cctalk <[email protected]>
> wrote:
>
> From all I have seen, Maurice Wilkes is considered the inventor of
> "microcode" as we know it. In the linked paper from 1951 he uses the term
> "micro-programme", so I think it is safe to say microcode was used in the
> same way in the 70s as it is today, although surely some people used it for
> normal machine code. I have seen examples of that, although none come
> immediately to mind.
> https://www.cs.princeton.edu/courses/archive/fall09/cos375/BestWay.pdf
From what I understand, the Dutch computer ZEBRA (a Dutch acronym for "very
simple binary computer") by van der Poel is, in a way, a machine in which
horizontal microprogramming is the way that regular programs are written. I
haven't looked at it in detail but the impression I got is that it uses the
horizontal microprogram approach of controlling individual elements of the
machine concurrently by the various fields of the instruction word, rather than
defining "normal" instructions that perform a single conceptual action at a
time. That machine actually predates the Wilkes paper.
https://en.wikipedia.org/wiki/ZEBRA_(computer) has more.
paul
