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Zip Drive Notes
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This note describes the results of testing IOmega Zip drives with the Tandy 1000
RL, RLX, and TX. I tested all the Zip drives beforehand on a 386 running MS-DOS
6.22 and Windows for Workgroups 3.11.
The RLX has a standard bidirectional port and a 286 processor. The RL has a
unidirectional 25-pin port and an 8086 processor. The TX has a card-edge
parallel port and a 286 processor.
The standard IOmega DOS driver worked fine with the built-in parallel port on
the RLX, for both 100MB and 250MB drives. Using the system setup program
(SETUPRLX), I set the parallel port to bidirectional. I then ran IOmega's
optimization program (OPTPPM1.EXE) to find the fastest settings for the Guest
driver. The RLX could use the byte driver in bidirectional mode at speed 10,
the fastest possible settings for a standard bidirectional port. The Palmzip
driver also worked on the RLX (see below).
On the RL, the IOmega driver could not be used since the RL only has an 8086
processor (attempting to use it locks up the machine). I used the Palmzip
driver obtained from this site:
http://leute.server.de/peichl/palmzipe.htm
The driver there was version 1.22. Before that, I tried Palmzip version 1.21
from this site:
http://www.palmzip.de/
That version DID NOT work, or rather, it appeared to work, but there were random
data errors in both reading and writing the Zip drive. It is important to make
sure you have the latest version of Palmzip. Palmzip is available as a free
test drive version that runs for 7 minutes; the full version cost me $10 US.
The parallel port on the 1000RL is unidirectional. According to Tandy's Tech
Notes and Jumpers Manual, the port can be used bidirectionally if jumper pins
are installed at positions E2-E3-E4, with a jumper on pins E2-E3. I made this
modification, but it made no difference; the Zip drive was not detected.
Instead, I installed a secondary parallel port card. The first parallel port
card I tried with the RL made the monitor screen shake (probably because of
power issues), but it would work to a degree after a few minutes. The second
card I tried was newer, with fewer chips on it and did not display this problem.
(The power supply in the 1000RL is only 25 watts, and I had already maxed out
the memory and installed a 40MB hard drive.)
Jumpering the expansion card for LPT2: did not work; it interfered with the hard
drive. I ran SETUPRL /A and disabled the built-in parallel port, then jumpered
the card for LPT1:. That finally worked, with Palmzip version 1.22.
The RL was running DOS 3.3. With versions of DOS below 4.0, Palmzip provides
for partitioning the Zip disk into 3 parts, using the included Zipman program.
Hence the Zip drive on my RL was seen as drives F:, G:, and H: (the hard drive
was C: and E:, the ROM drive was D:). The IOmega driver can only access the
first partition of a Zip drive that is formatted thus, but it can read and write
that partition just fine. (There is a way to enable access to all three
partitions on a machine running IOmega's driver, but I didn't try that.)
The TX has a unidirectional card-edge parallel port. To plug in a Zip drive, I
needed to build a port adapter. Jim Sandlin gives instructions for doing so on
his site:
http://users2.ev1.net/~switchtech/Tandy1000_DB25.html
I built the adapter and tested all pins for continuity. I then checked it by
connecting a DMP-130 printer to it using cable 26-227. The adapter worked with
the printer.
As indicated by the Tech Notes and Jumpers Manual, I then installed a jumper on
pins E11-E12 to connect the Select signal for input. As with the 1000RL, it did
not work. The TX could not detect a Zip drive attached to its built-in parallel
port.
The TX's parallel port cannot be disabled. I installed a parallel port card in
an expansion slot, the same one that had caused the monitor to shake in the RL;
in the TX, the card worked with no problem (the TX has a 67 watt power supply).
I jumpered the card for LPT2: and IRQ 7 (the hard drive uses IRQ 5). That
worked with Palmzip, which requires the /LPT2 option in this case. The IOmega
driver also worked on the TX when I booted it with DOS 6.22, but that version of
DOS is not ideal for the TX (which has no HMA or upper memory).
According to old messages in comp.sys.tandy, IOmega's driver worked in the
1100FD laptop, which came with the V20 processor. It is likely that it would
also work in a 1000-series model where the 8088 or 8086 processor has been
upgraded to a V20 or V30, but only with a parallel port on an expansion card,
not with the built-in parallel port. Palmzip would work on such systems without
a processor upgrade, however.
Palmzip does not work with Zip 250 or 750 drives, Zip Plus (combination
SCSI/parallel) drives, or newer Zip 100 parallel drives. According to the Zip
Drive Mini-Howto (refer Linux), the parallel Zip drive actually contains a SCSI
controller hence is really a SCSI drive. There is a chip called VPI0 that
connects the SCSI bus inside the drive to the parallel cable. Later Zip drives,
including the Zip Plus, Zip 250, and Zip 750 used a different interface chip
called VPI2. Under Linux, there are two different drivers for the different
interfaces (ppa.c for VPI0, imm.c for VPI2). Palmzip is probably supporting
VPI0.
Not all Zip 100 drives will work with Palmzip; the newest ones will not. So how
do you tell which drives will work? Zip drives may be model Z100P or Z100P2;
Z100P is older. They may have a full date on them (e.g., 03/21/99), or just a
month and day (e.g., 09/22), or no date at all. The ones with no date are
oldest (the ones I had had ROM dates 1995 and 1996), followed by the ones with
month and day (ROM dates 1997 and 1998), followed by the drives with a full
month, day, and year. I only tested one model Z100P, but I suspect they will
all work with Palmzip. With model Z100P2, the ones I tested with no date or a
month/day date worked, as did the ones with full date up to April 1999. Of the
Z100P2's I tested, only one, with manufacture date 1/24/2000, did not work with
Palmzip, though it worked fine with the IOmega driver.