Xref: utzoo comp.sys.mac:32997 comp.protocols.appletalk:2069
Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!apple!apple.com!teener
From: teener@apple.com (Michael Teener)
Newsgroups: comp.sys.mac,comp.protocols.appletalk
Subject: Re: direct ethernet connected Laserwriters
Message-ID: <2216@internal.Apple.COM>
Date: 6 Jun 89 00:17:25 GMT
References: <917@merlin.bhpmrl.oz>
Sender: usenet@Apple.COM
Organization: Apple Computer
Lines: 23

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 
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