Path: utzoo!attcan!uunet!cs.utexas.edu!sun-barr!olivea!orc!inews!iwarp.intel.com!omepd!omews35!colwell
From: colwell@omews35.intel.com (Robert Colwell)
Newsgroups: comp.arch
Subject: Re: Multiprogramming the Microcode: The B1700
Message-ID: <6120@omepd.UUCP>
Date: 18 Oct 90 17:00:37 GMT
References: <1990Oct4.001346.4139@Stardent.COM> <8052@scolex.sco.COM> <2926@sequent.cs.qmw.ac.uk> <1990Oct11.164904.12550@zoo.toronto.edu> <27843@bellcore.bellcore.com> <1990Oct14.001905.19442@zoo.toronto.edu>
Sender: news@omepd.UUCP
Reply-To: colwell@mipon2.intel.com (Robert Colwell)
Organization: Intel Corp., Hillsboro, Oregon
Lines: 19

In article <1990Oct14.001905.19442@zoo.toronto.edu> henry@zoo.toronto.edu (Henry Spencer) writes:
>The B1700 didn't have
>the Alto's multiple microcontexts, which made microprogram context
>switching effectively instantaneous and permitted using microcode
>to supply most of the smarts for most of the i/o devices.
>The Dorado, and perhaps
>some of the other Xerox D-machines, copied this approach, but nobody else
>has that I'm aware of.

Alas, the world has already forgotten the Three Rivers Computer Perq.  Ok,
so the arch. was borrowed wholesale from the Alto.  But it did all the
stuff you're talking about above.  And if the durned micros hadn't gotten
so good so quickly this type of arch. approach might have actually made
some sense.  Hindsight is so easy compared to prediction.

Bob Colwell  mipon2!colwell@intel.com  503-696-4550
Intel Corp.  JF1-19
5200 NE Elam Young Parkway
Hillsboro, Oregon 97124