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                               I/O EXTENDER
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                               SERIAL PORT

There are a lot of problems when using the hard drive host adaptor with the
Amiga's serial port (see:  SCSI HOST ADAPTER for more information), so GVP
put a 16-byte FIFO buffered serial port directly on the G-Force.  Normally
this would be very exciting, but I couldn't get it to work properly.  When
using the G-Force serial port, my computer eventually locks up (it doesn't
crash - it just freezes right after it spews garbage through the serial
port.) Any rate above 38,400 doesn't seem to "sync" up with some devices.
These problems make the port virtually unusable for high speed transfers
while multitasking.  This brings up another point.  I got many errors when
I tried formatting three floppies simultaneously while on-line at 38,400
with the G-Force port, but hard drive activity didn't cause any problems.

I did a number of things in an attempt to fix the problem including
changing the various buffer sizes, using different cables, and trying
different devices.  GVP informed me that increasing the buffers isn't
necessarily the correct thing to do, as it could cause more problems than
it fixes.  Indeed, this proved to be true.  Keeping the buffers between
4,096 and 16,384 bytes seemed to yield the best results, keeping the
machine from locking up for a longer period of time.  There was even a
program on AmiNet called "GVPIOPatch" (not related to GvpPatch) whose
description claims that the current serial drivers (1.7/1.8) use only 2
bytes of the 16-byte buffer on the port!  The patch claimed to fix that and
some other small bugs.  Using the patch did seem to free up some CPU time
during high speed transfers, but I can't say for sure whether GVP really
doesn't use the extra buffers or not.


                               PARALLEL PORT

The parallel port worked with the four printers I was able to test it with
Panasonic KX-P 1091i, Panasonic KX-P 2123, Epson LX-80 Spectrum, and
Brother HL-10H Laser Printer).  I had no problems sending data.

The problem I encountered was getting programs to redirect their output to
the new port.  Some programs (especially ones with PostScript® support)
will allow you to specify a port to print to, most programs will not.
GVP's solution, GVPIOcontrol, will forcefully redirect output at the
expense of simultaneously using your internal parallel port.  ALL
references to your internal parallel port, not just the PRT: device, will
be redirected to the port chosen in the IOControl preferences.

There is a program available on AmiNet called "ParPrefs" which is a much
better solution.  ParPrefs will allow you to redirect output to ANY device
(not just gvppar.device) meaning that it's compatible with other cards,
too.

Another solution involves AmigaOS 3.x and a release called "prt4248.lha",
which is an updated Printer Preferences program and printer.device.  Since
I do not have OS 3.x, I was not able to install the new Printer
Preferences.  However, I have read that it will allow you to select the
printer device and unit number and includes support for up to 25 printers
running simultaneously.

The final solution I have to offer requires a seperate program to watch one
of your directories (similar to "watch" folders on the Macintosh).  Art
Department Professional comes with just such a utility (File Sentry).  In
this case, you would create a spool directory and set up the watch daemon
to check for files written in it.  If you want to print a file through the
GVP port, you will then run the "CMD" utility that came with your OS and
make sure you redirect the output to the watch folder.  By default, CMD
redirects output to the RAM disk.