> On 2020, Aug 10, at 10:02 AM, Noel Chiappa 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: > > HOST MIT-SPOOLER, LCS 2/200,SERVER,TFTPSP,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 ) 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 and a patent 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 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.