Self modifying code, lambda calculus - Re: ENIAC programming

Jon Elson elson at
Thu Sep 17 22:55:39 CDT 2015

On 09/17/2015 08:40 PM, ben wrote:
> On 9/17/2015 6:50 PM, Jecel Assumpcao Jr. wrote:
>> This conclusion should have been obvious to anyone 
>> thinking about
>> general purpose computers implemented with microcode in ROM.
> Are there any computers that do let you put microcode into 
> RAM now-days.
> You have a lot of byte code virtual machines out there.
The 370/145 had microcode in static RAM, in a region of main 
storage, the first 64 K was a faster bank of SRAM, if I 
remember correctly.
The wall between microcode and regular main storage was 
movable, and selected by the microcode.

I think the later X86 machines have a tiny block of patch 
microcode that is available to the OS to put special 
routines into.


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