ianh@merlin.bhpmrl.oz (Ian Hoyle) (06/05/89)
Is the speed of printing for the NTX printer governed by how fast the
print engine can write the postscript image (and interpret the postscript file),
or is there a bottleneck with the speed of the localtalk connection?
Has any work been done on directly connecting a Laserwriter to ethernet and
have it communicate using EtherTalk ??? (is this possible ?? :-)
ian
--
Ian Hoyle
/\/\ Computer Systems Superintendent
/ / /\ BHP Melbourne Research Laboratories
/ / / \ 245 Wellington Rd, Mulgrave, 3170
/ / / /\ \ AUSTRALIA
\ \/ / / /
\ / / / Phone : +61-3-560-7066
\/\/\/ ACSnet : ianh@merlin.bhpmrl.oz.au
Internet: ianh%merlin.bhpmrl.oz.au@uunet.uu.netteener@apple.com (Michael Teener) (06/06/89)
In article <917@merlin.bhpmrl.oz> ianh@merlin.bhpmrl.oz (Ian Hoyle) writes: > Is the speed of printing for the NTX printer governed by how fast the > print engine can write the postscript image (and interpret the postscript file), > or is there a bottleneck with the speed of the localtalk connection? Right now, the major difficulty is with the Postscript interpreter. Note that a Laserwriter page is 8 by 10.5 inches, 300 dpi -> 7.56 Mbit. If we assume 8 ppm, then we only need 1 Mbit/sec effective rate to transfer a complete bit map (since Postscript sends bitmaps as hex, then we really need a bit over 2 Mbit/sec). The actual size of a postscript file tends to be quite small, compared to the equivalent bitmap, so the 230 kbit/sec Localtalk rate is not much of problem. Of course, this all changes when the print engine gets faster .... but for normal Postscript, particularly text-only files, the print engine will have to get LOTS faster before Localtalk becomes a significant bottleneck. ---- Michael Teener -- 408-974-3521 ---- Internet teener@apple.com, AppleLink TEENER1 ----- ---- Apple may know my opinions, but probably does not endorse them --------------------------------------------------------------------------- (Physical transportation by Cheetah N9900U, a loyal beast for the past 5 years)
liam@cs.qmc.ac.uk (William Roberts) (06/07/89)
In article <917@merlin.bhpmrl.oz> ianh@merlin.bhpmrl.oz (Ian Hoyle) writes: >Is the speed of printing for the NTX printer governed by how fast the >print engine can write the postscript image >(and interpret the postscript file), >or is there a bottleneck with the speed of the localtalk connection? It depends. If you ship a 500 byte recursive PostScript program then the bottleneck is probably in the graphics. If you ship a bitmap carefully arranged to be monochrome, at the printer pixel resolution and correctly aligned along the "grain" of the printer's framebuffer, then LocalTalk is the bottleneck. >Has any work been done on directly connecting a Laserwriter to ethernet and >have it communicate using EtherTalk ??? (is this possible ?? :-) I asked Glenn Reid this about a month ago and he said "It would simplify the PostSCript interpreter because it would then be dealing with only one real-time device, i.e. the laser". He said they haven't done it, and no-one looked as though they were trying to hide anything when I mentioned the idea at the Apple Developer Conference in Sna Jose last month. I'd like to see such a thing for a lot of reasons: 1) It separates control information from data, so binary images work (this isn't possible on the serial line connection) 2) It would cut out the need for LocalTalk, since all our Macs have ethernet interfaces 3) It would make it worthwhile for UNIX box vendors to include the AppleTalk protocol stack (e.g. the Kinetics implementation) as standard. This makes it easy to connect these wonderful PostScript printers, plus being easier to interwork with Macs, and the whole lot sets itself up with minimal administrator intervention. Come on Apple - how about a LaserWriter NTE? -- William Roberts ARPA: liam@cs.qmc.ac.uk Queen Mary College UUCP: liam@qmc-cs.UUCP AppleLink: UK0087 190 Mile End Road Tel: 01-975 5250 LONDON, E1 4NS, UK Fax: 01-981 7517