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From: dplatt@coherent.com (Dave Platt)
Newsgroups: comp.sys.mac.misc,comp.periphs.printers
Subject: Re: JetLink Express 1.2 vs HP DeskJet 500
Message-ID: <91870@coherent.coherent.com>
Date: 27 Nov 90 23:47:14 GMT
Followup-To: comp.sys.mac.misc
Distribution: comp
Organization: Coherent Thought Inc., Palo Alto CA
Lines: 35

About a month ago, I posted a note about an bug I'd run across in GDT
Softworks' JetLink Express printer-driver, which caused the driver to
fail to work reliably with the new HP DeskJet 500 printer.  I had sent
GDT an analysis of the problem (thanks to Dave Neff of HP) and requested
that they fix the bug.

I just got a call back from one of their tech support people.  Synopsis:

-  The bug was just as Dave Neff described it... the driver was
   generating some improper PCL escape sequences.

-  The programmer apparently knew that this would happen, and was
   depending on the printer's error-recovery logic to discard the
   incorrect sequence.

-  The DeskJet 500's error recovery logic doesn't catch this one case;
   the older DeskJet printers did detect and ignore the error.

-  The programmer has added an additional test to the DeskJet 500 version
   of the driver, to ensure that the improper PCL sequence won't be
   generated.  This slows down the driver a bit... how much, they're not
   sure (it depends on the usage patterns).

-  The new DeskJet 500 driver will actually outperform the older DeskJet
   and DeskJet Plus drivers by quite a bit, even with the additional
   error test in place, because it takes advantage of the DeskJet 500's
   two-dimensional raster compression algorithm (essentially the same
   algorithm that the DeskWriter uses).

-  GDT is sending me a beta-test copy of the new DeskJet 500 driver to
   test out.

-  GDT will be releasing JetLink Express 2.1 in a few weeks; it will
   include the DeskJet 500 driver, as well as a driver for the LaserJet
   IIIP.