Xref: utzoo comp.misc:2421 comp.arch:4868
Path: utzoo!utgpu!water!watmath!clyde!att!ncr-sd!steves
From: steves@ncr-sd.SanDiego.NCR.COM (Steve Schlesinger)
Newsgroups: comp.misc,comp.arch
Subject: Writable Microcode
Message-ID: <2223@ncr-sd.SanDiego.NCR.COM>
Date: 18 May 88 19:38:23 GMT
References: <2006@sugar.UUCP> <53583@sun.uucp>
Reply-To: steves@ncr-sd.SanDiego.NCR.COM (0000-Steve Schlesinger)
Organization: NCR Corporation, Rancho Bernardo
Lines: 13

>> Imagine a version of the microprogrammable chip in which the operating
>> system could context switch among trusted sets of microprograms.  Weird.

No. Not weird.

>
>Weird, maybe, but did not the Burroughs 1700 series do this a long time ago?

The NCR 8000 and 9000 series have writable control store today.
They support multiple instruction sets in the standard product line.
The 9300 had a Forth microcode set written for it.
Some university (I forgot which) wrote a Prolog instruction set
in microcode.