I spent a couple of hours today playing with the NeXT computer and can add
the following to the discussion (from a non-Adobe person, of course): The
NeXT computer's use of DP involves a binary preprocessor which helps to
alleviate the overhead associated with passing readable ascii
representations of numeric values. Definitely check out the November issue
of BYTE which features a highlighted description of display postscript and
how it was used in the NeXT implementation. The description goes into the
concept of "front" and "back" adaptors that were used to assist in
source-code interfacing with the environment. Also, a developer from Frame
told me the port from SunWindows to DS was fair and that the port from BSD
4.3 to NeXT's Mach/4.3 compatible OS was effortless. One important point to
bring out was that DS on NeXT was very impressive and appeared to operate
without any performance problems. The Byte article was based on an earlier
release of DS so its suggestion that DS is slow doesn't appear, at this
time, to be accurate.