Path: utzoo!attcan!uunet!seismo!sundc!pitstop!sun!coherent!dplatt
From: dplatt@coherent.com (Dave Platt)
Newsgroups: comp.sys.mac
Subject: Grappler LS (was Re: Tested the HP DeskJet driver by DataPak)
Message-ID: <13670@coherent.com>
Date: 9 Nov 88 22:06:02 GMT
References: <13240@coherent.com> <17269@vax5.CIT.CORNELL.EDU>
Reply-To: dplatt@coherent.com (Dave Platt)
Distribution: comp
Organization: Coherent Thought Inc., Palo Alto CA
Lines: 75

In article <17269@vax5.CIT.CORNELL.EDU> pv9y@vax5.cit.cornell.edu (Adam) writes:
 
> Has anyone done this kind of testing on the Grappler LS from Orange Micro?
> It seems to be about the same price, but does everything in hardware so it
> won't have problems when Apple upgrades to new drivers.  I'm interested in
> a DeskJet, but can't tell which interface is better.  Any suggestions?

I haven't tested the LS... last I heard (about a month ago) it didn't
seem to be shipping yet.

However, I've talked with people who have tested the Grappler LQ with
the DeskJet, though... and I infer (from what I've heard) that the LS
is an LQ-like device/package that's specific to the DeskJet.

The reports I've heard re the LQ with the DeskJet were relatively
disappointing;  the print quality wasn't great, and the printer ran
quite slowly.  I gather that there are a few reasons for this:

1) The Grappler LQ works with Apple's ImageWriter LQ driver, and
   rescales the IW/LQ's 216 dot/inch output to the 300 dot/inch format
   expected by the DeskJet.  The IW/LQ driver can use 3x-oversize
   fonts, but doesn't use 4x-oversize fonts such as can be used by the
   DataPak driver and by Apple's own LaserWriter IISC driver.  For this
   reason, output created via the Grappler LQ can't really match the
   quality of the LaserWriter IISC, of the DataPak driver, or of the
   printer's own built-in and ROM-cartridge fonts.

   If the Grappler LS also uses the ImageWriter LQ driver, I expect it
   would have the same limitations in this respect.  If, on the other
   hand, the Grappler LS uses the LaserWriter IISC driver, and connects
   via the SCSI port rather than over the Mac's serial printer port,
   then the LS might be able to produce true 300 DPI output.

2) The Grappler LQ has no way to make intelligent use of the printer's
   build-in and cartridge fonts (except, perhaps, for the built-in
   Courier 12-point font in draft mode).  The Grappler LQ software and
   hardware never "see" the QuickDraw codes generated by the user's
   application, and thus cannot instruct the printer to activate its
   own fonts when appropriate;  the Grappler LQ can only rescale the
   bitmaps generated by the ImageWriter LQ driver.

3) Shipping a page full of bitmapped data over the 19.2 kbit/second
   serial line to the DeskJet (via the Grappler LQ) takes quite a
   while... up to 6 minutes/page if data compression isn't/can't be
   used.  If the Grappler LQ or LS can use the DeskJet's parallel
   ("Centronics") port rather than the serial port, it might be
   possible to cut the time significantly.

I believe that the "Grappler LQ" technology has some inherent limits:
it can't produce "true" 300 DPI output (only rescaled 216 DPI bitmaps),
can't use the HP font cartridges, and is relatively slow.  Any DeskJet
driver that works by emulating an ImageWriter LQ would have these
disadvantages.

A higher-performance approach would be to emulate the LaserWriter
IISC.  Such an emulator might connect to the Mac's SCSI bus, and to the
DeskJet's Centronics-compatible parallel port.  It would not need to
perform any rescaling at all, because Apple's driver for the IISC
creates 300 DPI bitmaps using 4x-oversize fonts;  it could transfer
data to the printer much more quickly (at SCSI and Centronics-parallel
speeds) after a simple SCSI-block-to-HP-PCL reformatting.  It would be
substantially immune to changes in the Mac's printer-driver interface,
and would probably continue to work after Apple's proposed interface
changes.  It probably couldn't make intelligent use of the HP fonts,
but this might be less of a disadvantage due to the emulator's higher
potential throughput.

Has anybody out there actually seen or played with a Grappler LS
attached to a DeskJet?  How does it work?  How _well_ does it work?

If anyone has regular access to this beast, please drop me a note...
perhaps we can agree upon some test data (a few documents of mixed text
and graphics?) and some testing procedures.  A real apples-and-apples
comparison between the Grappler LQ, Grappler LS, and the DataPak driver
could be a _very_ useful bit of work!