🚀 go-pugleaf

In article <532@gt-eedsp.UUCP> jensen@gt-eedsp.UUCP (P. Allen Jensen) writes:
>In article <1740@eos.UUCP>, lyman@eos.UUCP (Lyman Taylor) writes:
>>.....
>> 	A possible solution to this is that perhaps there no COMPUTER inside
>> the [laser printer].
>The laserprinter has no computer - Or memory - It uses the NeXT
>CPU for everything and sends an image over a "special high-speed"
>laser printer interface.  Looks like it will only work on the NeXT
>box !
	For the Mac II, I have the General Computer Personal Laser
Printer (PLP).  As with the Apple Laserwriter IISC, it connects to the
computer via SCSI.  There is a processor in the laser printer, but it
does not interpret Postscript (or anything else remotely complicated).
It does have some memory, but I don't believe it has enough for
anything like a page of bits (about a Megabyte is required).  As far
as I can tell, the host rasterizes the stuff & sends it to the
printer.  SCSI, the printer's CPU, and the Mac are quick enough to get
the data to the drum so that it is not slower than having a CPU & RAM
inside the printer.
	I haven't a clue as to what interface the NeXT machine uses.
I hope it is SCSI.  The NeXT machine does support SCSI, therefore, it
should be possible to support IISC & PLP printers on it, as they
describe, at 300 dpi.
	While this is pretty much Mac specific (Mac II, SE, plus if
SCSI is available), it is only due to the software availability on the
Mac.  If one had SCSI on a PC (clone), and software that could talk to
it, these printers should work.
	The advantages of Postscript (or some sort of language) in the
printer are:
1. The data sent to the printer is smaller.
2. The host doesn't have to rasterize the document.
	The advantages of having the host do it are:
1. If there is a bug in the language, it can be fixed (it is just
   software).
2. More than one language can be supported (it is just software).
3. It is cheaper.  A PLP goes for around $2K.  A Laserwriter Plus is $3.5K.
	This last point is interesting.  For the Apple Laserwriter II
series, one can upgrade the printer to something stupid like 12 MB of
RAM, a 40 MB (80?) hard disk, etc.  For people who didn't start with a
16 MHz 68020 (or better), the printer is a much faster machine with
better resources than the host.
	For the PLP, I can upgrade my Mac II to something stupid like
8 MB of RAM and lots of hard disk.  Further, I can use this same RAM
and disk for things unrelated to printing.

	One argument goes that having the smarts in the printer allows
the host to go on working while the printer prints, thus freeing the
host.  For the Mac, this isn't generally true.  It is probably only
true for the last few pages of text.  The Mac often has to convert
what is doing from quickdraw, or a rasterized bit plane to postscript
anyway.  Finally, it ships it to the printer, and waits for it to get
there.
	Curiously, for the NeXT machine, it is more true.  The OS
there is a true multuser OS.  Time spent degrades the performance of
the rest of the machine (potentially, the network).  In a workstation
environment (a Mac or NeXT, but not here at the office), the CPU is
idle most of the time (otherwise it is not a very good workstation),
and so you may as well let it be *able* to do something now and then.
One could make a strong argument that a good workstation is one that
is able to do lots of stuff, but never seems to spend any time doing
anything.
	I haven't been following the industry too closely, but I'd
probably pay real money (but not too much) for a postscript system
that will run on my Mac that will talk to my PLP.  Now that it has
been done for the NeXT machine, it should be easier.
	I think, though, I'll work on making quickdraw act like it
really knows the PLP (at 300 dpi for everything), and devise some
scheme for transfering tiny ASCII based text+graphics files around
such that they can be used on a variety of machines (host type +
printer type) for a variety of applications (including real word
processing).
	Stephen.