Xerox Alto emulator(s)

From: Derek Peschel <>
Date: Sun Jul 16 05:04:06 2000

> I was just thinking...Would it be possible in 2000 to write a Xerox Alto
> emulator and SmallTalk OS (assuming binaries are available). Is there any
> efforts underway? personally I've love to experience an Alto, but unless an
> emulator happens this is never going to happen. Historically it's a very
> significant machine..and it would be neat to preserve it for future
> generations.

Ask Al Kossow. He's supposedly been working on one for a while.

> What makes it difficult to write an emulator for this machine?

Probably the fact that you have to emulate the microcode. Some of the Alto
software was written in BCPL and used an instruction set geared for running
BCPL programs (which may have been similar to the Data General Nova's set).
But fire up Smalltalk or LISP or Mesa and you're suddenly using an entirely
different instruction set.

You might be able to emulate each instruction set as a special case, but it
would probably be safer to emulate the microinstructions that create the
instruction sets. The microcycle time is 170 nanoseconds, so it might just
be possible on current hardware if the OS doesn't get in the way.

Supporting the 3MB/sec Ethernet might be a challenge too.

-- Derek
Received on Sun Jul 16 2000 - 05:04:06 BST

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