[TUHS] BTL summer employees

Lawrence Stewart stewart at serissa.com
Tue Aug 11 03:08:20 AEST 2020

> On 2020, Aug 10, at 10:02 AM, Noel Chiappa <jnc at mercury.lcs.mit.edu> wrote:
>> From: Lars Brinkhoff
>> I haven't investigated it thoroughly, but I do see a file .DOVR.;.SPOOL
>> 8 written in C by Eliot Moss.
>> ...
>> When sending to the DOVER, the spooler waits until Spruce is
>> free before sending another file.
> Ah, so there was a spooler on the ITS machine as well; I didn't know/remember
> that.
> I checked on CSR, and it did use TFTP to send it to the Alto spooler:
> I vaguely recall the Dover being named 'Spruce', but that name wasn't in the
> host table... I have this vague memory that 'MIT-Spooler' was the Alto which
> prove the Dover, but now that I think about it, it might have been another one
> (which ran only TFTP->EFTP spooler software). IIRC the Dover as a pain to run,
> it required a very high bit rate, and the software to massage it was very
> tense; so it may have made sense to do the TFTP->EFTP (I'm pretty sure the
> vanilla Dover spoke EFTP, but maybe I'm wrong, and it used the PUP stream
> protocol) in another machine.
> It'd be interesting to look at the Dover spooler on ITS, and see if/how one
> got to the CHAOS network from C - and if so, how it identified the protocol
> translating box.
>   Noel

“A pain to run” and “tense” indeed!  The Dover printing system was an Alto (6 MIPs <microinstructions>) driving “Orbit” hardware about half the size of the Alto itself*, driving the raster video to the printer.  The hardware was called “orbit” because it could directly “OR” bits into the raster image, rather than requiring read-modify-write cycles.  “Spruce” was the spooler and printer driver that ran on the Alto.  Evidently the hardware is a typical Butler Lampson knife edge design up in the corner of what was possible, implemented by Bob Sproull and Severo Ornstein.  Additional software by Dan  Swinehart.

There’s a page about this in https://bwlampson.site/38-AltoSoftware/Abstract.html <https://bwlampson.site/38-AltoSoftware/Abstract.html> and a patent https://patents.google.com/patent/US4203154 <https://patents.google.com/patent/US4203154>.  I have a feeling I’ve seen a longer description of Orbit somewhere but I can’t remember where.

Like most Stanford folks of the era I printed my thesis on one, assisted about 1 AM by Lyle Ramshaw who knew where to get a new drum for the printer.

In any event, a vast improvement over the XGP and a godsend for those of us who <didn’t> have a phototypesetter.

* An earlier one-off called EARS had printer hardware about 3 times the size of the attached Alto.  That one was font-image based.  To do things like lines and  graphics the software constructed custom font glyphs to make up the image.

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