Fred Cisin wrote:
  "EMS"/"Expanded" memory
 is simply bank switching. 
...
  So, he developed a laser printer interface (JLASER for
Canon CX)
 that did all of the rasterizing, etc. in the host computer,
 and THAT took some RAM! 
I used a JLASER card for my first explorations of PostScript, way
back in 1987.  I worked for a small software house called London
Software Studio, and we wrote presentation graphics software.  One
of our plans was to add a postscript hard-copy option, so that
users could make high-quality printouts and OHP transparencies.
I still have the PostScript code that I wrote on that thing, using
a Victor 286 machine as the host.
--
John Honniball
coredump(a)gifford.co.uk