The PERQ factor (was: One-upsmanship) (fwd)

From: Peter C. Wallace <pcw_at_mesanet.com>
Date: Sat Apr 20 09:52:02 2002

> > I think the most beautiful processor I've seen is CPU card of the
> > Symbolics 3645. The wiring and chip layout are really nice. One thing that
> > always impressed me about that machine is that the disk label is in ASCII
> > text! Of course it has a 68000 with a decent amount of ROM space (the FEP) to
> > boot from...
>
> What do you mean by "the disk label is in ASCII text"?

Its been a long time (>10 years) but AFAICR I was able to add a new Saber
drive by using the FEP, The disk label is just plain text in the first block
that is interpreted...

>
> I've played with a Symbolics for maybe half an hour. It has a lot of cool
> software, though it kept trying to connect to a ChaosNet server to download
> all the docs, so there was a lot I couldn't find out. I haven't really
> explored the essence of the software.

1/2 and hour with an incomplete system is not much of a demonstration...

>
> The design of both the software and the hardware strikes me as baroque
> (typical MIT "just keep adding features" hacking). Also the system as a
> whole is not necessarily "self-sustaining". A friend of mine is having
> trouble with his Symbolics -- his disk has bad blocks in the LISP world --
> he doesn't have the "breath-of-life" tape that has to be created for each
> individual disk -- there's no way for the FEP to change the bad block list
> -- the software to create new "breath-of-life" tapes is not available.
> If any of those problems were fixed things might be better, but in the
> current situation there's no recourse (except to pay Symbolics). That's
> what I mean by "not self-sustaining"


        I dont think that there was a whole lot there that was not needed. A
tagged architecture 36 bit machine with paged virtual memory, ECC, capable of
executing about 5 million Lisp instructions a second was not trivial to build
in 1985...

>
> I've read the manuals for the Xerox environment but I've never used the
> actual machine. The hardware/software is less baroque but still heavily
> layered (three separate LISP environments running on top of PILOT on a
> variety of machines with a variety of keyboard layouts). INTERLISP's
> comment handling never seemed sensible to me and it has lots of cryptic
> names and messages left over from the TTY days.

The Xerox hardware is less "baroque" because is is not a "Lisp machine" it is
a microcoded 16 bit processor with WCS. The magic is done with (very clever)
microcode but it is _much_ slower than the 36xx

>
> > The Symbolics and the Xerox WS running Interlisp always seemed to be
> > the most "alive" computers I've used, which I think has something to do with
> > how much the command interpreter, shell, etc knows about things...
>
> And how interconnected they are. I would love to play wtih DEdit (or SEdit
> which is the newer version) -- its generalization of "select, then act"
> to multiple selections and its "one man's output is another man's input"
> mentality would be fun. I don't know much about TEdit or the Grapher but
> they seem to have cult followings.
>
> -- Derek
>

You can download a Interlisp/common lisp environment from PARC that will run
under Linux (its actually an application (LFG)) but you can play with SEdit
and Tedit) ...


Peter Wallace
Mesa Electronics
Received on Sat Apr 20 2002 - 09:52:02 BST