Self modifying code, lambda calculus - Re: ENIAC programming

tony duell ard at
Fri Sep 18 08:33:05 CDT 2015

> > Are there any computers that do let you put microcode into RAM
> > now-days.
> "Now-days"?  There are some that do that, some of which are still in
> operational shape.  Some VAXen, in particular, have something called
> "writable control store", which is essentially microcode RAM.

As far as I know, the VAX11/730 (There is one next to me waiting for me to have time
to restore it) has the microcode entirely in RAM. Classic PERQs (3 in the next room) have
their microcode entirely in RAM too (in that case, there is a microcode boot ROM to load
the microcode from disk, but it is switched out after the microcode is loaded).


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