[texhax] TeX -> PostScript, but in a resolution-independent manner

Pierre MacKay mackay at cs.washington.edu
Thu Jun 5 17:08:38 CEST 2003

As one of the only people to actually run an Alphatype, I will answer that
Alphatype fonts were neither fish nor flesh.  They were a kind of outline font
in a highly proprietary format, with a notional resolution of 5333 lines/inch.
The Alphatype driver was a huge affair, written in--I can't even remember the
name, but it ran only on Dec10 and Dec20 machines, and big ones at that. 
The chief purpose of the Alphatype format, to put it bluntly, but not
unfairly (people at the company told me this) was to acquire fonts on the cheap
since the high resolution made fuzzy artifacts around the edges virtually
invisible.  The resolution was only notional.  David Fuchs did some experiments
that proved that the Alphatype format cut corners shamelessly.  

Perhaps the most innovative thing about the Alphatype was that it could
use CRT grade phototubes, in contrast with the incredibly high-resolution
VideoComp.  It formed characters letter by letter------s-l-o-w-l-y-------
on the screen, then positioned a set of mirrors and lenses to flash each 
letter on the cut-sheet photopaper.  worm gears then repositioned the photo
paper for the next letter.  The whole procedure was desperately soporific,
and the sound of the machine, with its worm-gears, lens transport and other
noises lead someone, I suspect it was David Fuchs, to send the message
"Begin the Beguine" when the Dec10 or Dec 20 (running SAIL, now I rmember)
finally got the machine running.  The internal program was on about 12
PC cards in an S100 bus, and there was no hold-down strap over the cards,
so that in a long run a few of the memory cards invariably jiggled loose,
and required that the whole thing be shut down and restarted.  

There were other peculiarities as well.  Advertisers liked the Alphatype
because you could piece together almost any size of poster font in increments
at a time when that was rather difficult on other machines.  Over about
18-point type sizes, even Computer Modern had to be pieced together that
way.  Once you started breaking characters up into bits, it was
hard to stop.  I produced one entire book in broken type, a refinement
that was not really noticeable except at the lower right corner of each
page, when the photo-paper transport started to get out of alignment.

Pierre MacKay

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