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Sketchpad? (off-topic)

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Casey Ransberger-2

Sketchpad? (off-topic)

Apologies for the off-topic question, but does anyone know if the actual bits for Sketchpad are still extant somewhere? Is there any documentation that anyone has for the Lincoln TX-2? It'd sure be neat to emulate it.

Someone was asking me about object oriented programming with a head full of Java yesterday and I wanted to point at some things. Recently I had a really great experience using an Apple IIgs emulator to explain HyperCard (kind of an odd version, but it worked,) and it dawned on me that if we wanted to learn history by doing, we really ought to grab at whatever bits are out there and curate the damned things.

And: selfish childish desire to play with Sketchpad!

Jecel Assumpcao Jr

Re: Sketchpad? (off-topic)

Casey Ransberger wrote on Sat, 19 Jun 2010 12:44:01 -0700

> Apologies for the off-topic question, but does anyone know if the actual bits
> for Sketchpad are still extant somewhere? Is there any documentation that
> anyone has for the Lincoln TX-2? It'd sure be neat to emulate it.

This first place to look for information about old computers is
BitSavers, such as

http://www.bitsavers.org/pdf/mit/tx-2/

> Someone was asking me about object oriented programming with a head full
> of Java yesterday and I wanted to point at some things. Recently I had a really
> great experience using an Apple IIgs emulator to explain HyperCard (kind of
> an odd version, but it worked,)

I had no idea that HyperCard ever ran on machines other than the classic
Mac.

> and it dawned on me that if we wanted to learn history by doing, we really
> ought to grab at whatever bits are out there and curate the damned things.
> And: selfish childish desire to play with Sketchpad!

Now that there is (or seems to be - I was unable to test) a reasonable
emulator for the Alto, it would be nice if some disk images for it were
publicly available. Specially any Smalltalk related ones.

http://www.bitsavers.org/bits/Xerox/Alto/simulator/salto/

Since Sketchpad only ran on a single computer in the whole world, even
in its day most people exposed to it experienced it as movies instead of
a live demo. These movies are available today. Certainly an emulator
would be nice, but the i/o devices on PCs are different enough from the
TX-2 that I don't know how realistic the experience would be. Even a
Vectrex (an interesting videogame from 1982) emulator is rather
different from the real thing (which I had the pleasure of seeing in
action live about four years ago)..

-- Jecel

alanone1

Re: [fonc] Sketchpad? (off-topic)

In reply to this post by Casey Ransberger-2

Hi Carl

The bits for Sketchpad are still extant. Ivan has them.

Brian Silverman -- who has done a number of really good emulators of old machines to run old software -- has tried for some years to get enough information about the TX-2 from Wes Clark (and the Sketchpad bits) from Ivan to get Sketchpad running again. Quite a bit of Sketchpad was written in CORAL, a macroassembler created by Larry Roberts, etc.

The largest problem is that TX-2 was an experimental computer that was used to try out many ideas (every Thursday it would be in the province of the HW people for "modifications"). The TX-2 joke was that it was "the only computer that could run with 10% of its wires disconnected!". So the HW was a bit of a moving target compared to most computers.

The Flex Machine and the Alto (and all PARC HW) used microcode that ran quite a bit faster than main memory to get much of the flexibility needed for experimental computing -- this made the Alto a much easier machine to emulate (though there were also some major deeper modifications over the years).

Cheers,

Alan

From: Casey Ransberger <[hidden email]>
To: Fundamentals of New Computing <[hidden email]>
Cc: The general-purpose Squeak developers list <[hidden email]>
Sent: Sat, June 19, 2010 12:44:01 PM
Subject: [fonc] Sketchpad? (off-topic)

And: selfish childish desire to play with Sketchpad!