parallel printers (Apple) on DEC Alphas

From: Lucio Chiappetti <lucio_at_ifctr.mi.cnr.it>
Date: Mon, 15 Dec 1997 19:25:11 +0100 (MET)

I am finding that an Apple Select 360 laser printer is printing slowly then
expected. The printer is attached to the parallel port of a DEC Alphastation
255/200.

 - we originally had one such printer attached to the parallel port of
   a Sun and another one attached to the serial port of another Sun. Of
   course the parallel one was way faster.
   We also had another Apple on Apple talk attached to a few Macs.

 - when we moved we assigned groups of workstations to a given printer
   (by location in the corridor) and we planned to attach printers both
   on parallel ports of machines which had one, and to a stretch of
   Apple talk (the printers support both ports at the same time).

   At the same time we bought also a network printer (HP Laserjet 5)

 - we originally planned to attach one Apple to an Alpha 200/100. To do
   this we needed a 10-m parallel cable. We (and DEC) were unable to make
   this work. DEC replaced three motherboards, and was unable to find a
   spec saying that it could or could not work. As a matter of fact it
   worked on the 200/100 with a shorter cable, and works on a 255/200 with
   the long cable.

 - so I had an hole drilled in the wall and attached the printer to my
   Alpha 255, and also to a Mac in Apple talk, just to exercise.

 - I had the feeling that the Alpha+Apple was somewhat slower than the
   Sun+Apple combination.

 - Instigated by a colleague, I've now run an handicap race between two
   of the closest printers, i.e. the Alpha+Apple and the network HP.
   I sent almost the same ps file to both (actually I needed two copy
   of the paper, one with footings and one without, so I sent the slightly
   bigger one to the HP).
   The file is a 1.9 Mega ps file produced by Word, with 8 ps figures
   imbedded, of which two are quite complicated contour maps, so it
   should be a significan test.

   The result was that the first 2 pages came out more or less in the
   same time, then the HP got ahead, and output the entire 8 pages in
   some 3-4 minutes, while the Apple took more than 20 minutes.

Both printers were not used by anybody else (and also the Alpha was quiet).
The Appletalk cable was attached (but no Mac were on).

There are also no errors in the lpd error file.


Is there any better way to test/exercise (and ultimately improve) the
performance of the Alpha+Apple combination ?

Could the presence of both parallel and Appletalk cables at the same time
interfere ?

Is the length of the cable a problem (I think not since on the 200/100 when
the cable was not working one was losing pages or entire print jobs, now they
come out OK) ?
What is the protocol between lpd and the printer ? could it be that there are
hidden errors and retransmissions ?

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Lucio Chiappetti - IFCTR/CNR - via Bassini 15 - I-20133 Milano (Italy)
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Fuscim donca de Miragn E tornem a sta scio' in Bregn
Che i fachign e i cortesagn Magl' insema no stagn begn
Drizza la', compa' Tapogn (Rabisch, II 41, 96-99)
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For more info : http://www.ifctr.mi.cnr.it/~lucio/personal.html
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Received on Mon Dec 15 1997 - 19:23:26 NZDT

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