Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!sun-barr!decwrl!henry.jpl.nasa.gov!elroy.jpl.nasa.gov!grian!alex
From: alex@grian.cps.altadena.ca.us (Alex Pournelle)
Newsgroups: comp.lang.postscript
Subject: Re: 9600 bps bottleneck on Laserwriter Plus
Message-ID: <1990Jan10.042555.19571@grian.cps.altadena.ca.us>
Date: 10 Jan 90 04:25:55 GMT
References: <3495@hub.UUCP>
Organization: Workman & Associates
Lines: 28

jim@cavevax.ucsb.edu (Oreo Cat) writes:

>The serial port on the host computer can be driven at up to
>38400 bps, but unfortunatley the serial port on the LW+ only goes up to
>9600.  I am told that the appletalk connection runs at something like
>64 kbps.  Is there any way of connecting this to a serial port?  Or is
>there any way of making the serial port run faster than 9600?
>  It now looks like we'll be printing more of the bitmaps, so any
>cheap solutions to this problem would be greatly appreciated!

I'll throw out an answer I thought up some time ago, and never
implemented.  Like all ideas, it's free; if someone does it, I'd like a
copy!  Apologies if this has been "done before"; I'm new here.  If it
has, I'd certainly like to know about it, having a similar problem.

Implement a postscript decompresso program--one that "unsqueezes" data
as it comes through the pipe--download it to the printer, then do the
reverse on the computer.  With some simple escapes, you could massively
increase throughput on nearly any large file.

Naturally, you'll have to hand-assemble the code on the host machine, in
order to see a significant increase in throughput.  But even a 2 to 3x
compression should be achievable easily, in total wall clock time.

Comments?
	
		Alex