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/// Usenet Review: GVP ioExtender
By J.P. Hillenburg
GVP ioExtender (With version 1.7 software)
The ioExtender is a Zorro II hardware product which expands your
Amiga 1500, 2000, 3000, or 4000 by two serial ports, one parallel port, and
one MIDI port, in an extensible manner. The ioExtender is capable of any
speed from 1 to 614400 baud. It also is designed to work cleanly with the
ports contained in the G-Force 040 accelerator. However, I was not able to
Name: Great Valley Products
Address: 600 Clark Avenue
King of Prussia, PA 19406
Telephone: (215) 337-8770
Facsimile: (215) 337-9922
$149.00 (US), with mailorder prices ranging from $110 to $130. I
paid $150, but in recent weeks the price seems to have dropped dramatically.
SPECIAL HARDWARE AND SOFTWARE REQUIREMENTS
Requires a Zorro II-capable Amiga.
No extra RAM is required, but 1 megabyte minimum is my
Does not require a hard drive, but the documentation
assumes that you are using one.
Does not require any particular CPU.
None. It's a Zorro II-based dongle. :)
MACHINE USED FOR TESTING
Model used: Amiga 3000
RAM: (Fast) 16 megabytes 70 nanosecond Static Column ZIPs
(Chip) 2 megabytes 80 nanosecond DIPs
Kickstart version 37.175
Workbench version 38.30
Tested with: Commodore MPS-1270 InkJet Printer
SupraFAXModem V.32bis (ROM version 1.200H)
Best Data 'Smart One' 2400X
I tested the ioExtender specifically with Terminus 1.926, AmigaUUCP
1.16D, DNet 2.10, GPFax 2.23, JR-Comm 1.02a, term 3.3, VLT 5.576, TrapDoor
1.80, TransAmiga BBS 1.1, and PrintManager 1.1.
In the case of all of the above programs, I was able to merely set
my serial device and go. Once the device was set, it was mechanically no
different than using the internal port. However, there was a noticeable
performance increase. CPU usage dropped drastically.
Unfortunately, selecting the parallel port for printer use is not so
clean. You have to use the supplied "GVPIOControl" program to intercept
parallel.device calls and route them to gvppar.device. I do not blame this
on GVP, but on Commodore, since selecting which hardware port printer.device
uses isn't nearly as easy as selecting serial devices. Audio digitizers
tend to hit the Amiga parallel port hardware directly; so this merely allows
you to use the I/O Extender to drive the printer, while the digitizer goes
along on its merry way, banging the internal parallel port.
GVP supplies 1/3 of a disk full of support programs, including
the driver program, a port-interceptor program, a serial preferences
program, an interceptor-preferences program, a system-information program,
and a program which even improves native Amiga serial.device performance.
The "GVPSerial" preferences program closely resembles the AmigaDOS
2.1 preferences, except for a few changes required for the board's nature
(e.g., selecting which particular port, and, if you have multiple ioExtenders
and/or a G-Force 040, which board).
The "GVPIOControl" program allows you to redirect the serial.device
and parallel.device to the gvpser.device and gvppar.device, respectively.
However, one should have to do this only with the parallel.device, as most
properly written, modern programs allow you to select the serial device
The "GVPIO" program simply goes in SYS:Expansion, and is the basis
for the software driver.
The "GVPinfo" program provides general system information. It
specifically recognizes the ioExtender, by full name. It also displays
information customary to this type of program, such as particular chips, RAM
information, etc. A similar program, Nic Wilson's "SysInfo", mistook the I/O
Extender for a GVP Series II SCSI Board. Commodore's "ShowConfig" program
identified the board as a generic hard-drive controller, but provided no
The "GVPPatch" program breaks up DMA packets to allow better
serial.device performance, which I assume would work for other devices as
The board itself contains two very-high-speed DB9 serial ports, one
DB23 parallel port, one MIDI sub-port, and one expansion port. The MIDI
port is a 9-pin port which attaches to an optional MIDI-expansion box. This
box gives you full MIDI-expansion capability, via one "In" connector, three
"Out" connectors, and one "Thru" connector. The expansion port is an
internal port directly on the board which allows later attachment of other
I/O related devices. I have heard mumblings of Ethernet capability for this
Documentation is provided in a 44-page plastic-bound manual. It has
instructions for board installation in the A2000 and A3000, but not for the
A4000. It also has clear, concise information on the necessary software,
but doesn't document the "GVPinfo" and "GVPPatch" programs. "GVPPatch" does
come with on-disk documentation.
The documentation provides application examples for JR-Comm and
AmigaVision, but assumes that the user would know how to use these to
other programs. (Not too difficult, however.)
It provides information which I would deem appropriate for someone
who is moderately versed in Amiga specifics. While not assuming the user is
a "technogeek" who knows the machine up and down, it is not for the weak at
LIKES AND DISLIKES
I like the fact that the ioExtender provided a fast, cheap,
addition to my system. It provided additional ports which I had needed.
I dislike the fact that the card was about 1 millimeter too large
for my A3000, requiring me to remove one of the beige clips which would
normally hold the front of the card in place. This particular process is
fairly easy, and involves prying the clip out of place with a screwdriver.
COMPARISON TO OTHER SIMILAR PRODUCTS
I have no real basis for comparison. However, I do wish it had the
7 serial ports as per the Commodore A2232. Those are only 19200 baud,
however. You can't have everything.
I have had no problems other than the clip removal, so have had no
need to contact GVP.
No conclusive warranty information given. I find this to be
disturbing, but not a deterring factor, as I have not ever seen or heard of
a problem with the board that a software upgrade did not fix.
I am happy with my ioExtender. It seems to perform well and as
I give it a 4 out of 5, as I feel it should have installed cleanly
without the requirement of removing the clip near the front of the machine.
There is a lot of empty space on the board, and I believe the board could
have been manufacturered to require a lot less space.