🚀 go-pugleaf

    Date: 18 Mar 87 01:52:31 GMT
    From: cbatt!osu-eddie!osupyr!akw@ucbvax.Berkeley.EDU  (FarOff MicroDesigns)

	...	The Mac (and hopefully the Atari
    laser printer) takes PostScript input, which is an object and line-oriented
    printer graphics language.  It doesn't require a complete bit-map of what-
    ever you want to print out.  This saves the hassle (and slow speed) of
    trying to bit-map an 8 1/2 x 11 page w/ 300x300 dpi in RAM instead of doing
    it by objects.   *Hopefully* this will be an option on the Atari printer
    so that programs that produce PostScript output (i.e. Publishing Partner,
    Graphic Artist, etc.)  A bitmap is too inefficient, expensive (at this
    time) and *slow*.  I hope that Atari will consider the PostScript or
    QMS language for its printer.  
	...

There are other people on this mailing lists who are experts but since I
am not with any manufacturer of laser printers, I can make comments freely.

The above implication that bitmaps are slow is wrong.  I can print a
bitmap of 1K by 1K pixels from my lisp machine to an Imagen printer
(non-Postscript (they have their own DDL)), standard Canon 8ppm print
engine with a 68K running it, I believe) and have it in my hands in
under 50 seconds (including processing time on the lispm, transit time,
and processing time on the Imagen).  (Imagen has an even faster
processor but we don't have it).  I once tried the same thing to a Apple
laserwriter and it took 4.5 minutes (same print engine, I don't know how
much time extra was spent in shipping the pixels from lisp machine to
print engine.. at 9600 baud, it would be under 2 minutes for a net 2.5
minutes).

I believe the general consensus is that Postscript processing by the
printer is one of the bottlenecks.

Most printer output would not be bitmaps.  When I print 8.5x11" pages
of 8-point text (all downloaded fonts, in my case) (about 100 lines/page,
130 columns), our Imagen 20ppm printer prints at very close to (exactly?)
the print engine's speed (20 pages/minute).  

But this forum is not the right place to discuss (or flame) about the
differences between Postscript and other alternatives.

As I understand the press release, the ST will be the CPU driving the
print engine itself.  (The MAC does not; the Apple Laserwriter does.
The Laserwriter I presume has to make at least a raster-by-raster bitmap
because the laser gets only one chance at each point on the drum (ie,
each point on the paper).  Creating an entire bitmap sounds easier when
you are really driving the laser.)  I would assume the ST could have
whatever code loaded the user wants to do that.  I wouldn't be surprised
if there was more than one alternative available eventually.  (I have no
knowledge about what is really going on at Atari other than what I have
seen on this list.)