RE: SCSI connector issues again (no stock discussion)
Brendan,
Lots of others already have pitched in here, but since
you addressed your post to me, here's my two cents.
First, um, I feel your pain. I got a PCI Jaz Jet, an
external SCSI Jaz, and an external SCSI Zip all at
once. I tried adding them to a PC that already had
an HP Scanjet IIcx scanner on it, and then to complicate
matters further, I tried to add a coupla old Bernoulli IIs,
one internal and one external, to the whole affair and to
convert my OS from WfW 3.11 to Win95, all at the same time,
on the theory that if you're going to be forced to eat
excrement, you don't want to do it in nibbles. So much
for my Christmas holiday in 1996.
Amazingly enough, I did get the whole thing working,
eventually, but it took some cabling gymnastics and
other tricks.
As you've at least partially found out already, there are
four background things to establish first. One is that,
under normal circumstances, all SCSI connections have
female/socket connectors on all the devices and cards,
and male/pin connections at both ends of the cables,
and they're designed to have only one cable, with
no adapters or gender-changers, between any two cards/
devices. Two is that a good SCSI connection is very,
very sensitive to cable length, so you should avoid using
multiple cables in series without any daisy-chained devices
in between them if you can, and indeed you'll find few
add-on aftermarket SCSI cables out there that will allow
such an arrangement. (That's part of the reason they
designed SCSI to be all-female in the cards and devices
and all-male in the cables, I think.) Three is that there
are three kinds of connectors, namely, the rather rudimentary
and traditional 25-pin SCSI-1 connector such as on the Zip,
the intermediate but traditional-looking 50-pin SCSI-2
connector such as the one on the cable Iomega sent you,
which doesn't help you, and the new, compact 50-pin
HD SCSI connector, suitable for Ultra connections,
that's on the Jaz external units and on the Jaz Jet
cards. Four, if you're going to connect a bunch of
SCSI devices together in a daisy chain running off
of your new card, hook up the ones having the 50-pin
HD connector closest to the PC if you can, then add
the ones with the more traditional 50-pin connector,
and then put the ones with the 25-pin last, farthest
out from the PC on the daisy chain. Then, if your
initial arrangement doesn't work, first you should
try rearranging them a little, and second you should
make sure your PC's BIOS is up-to-date, and of course
throughout it all you should check to make sure that
you haven't assigned any duplicate SCSI ID numbers to
any of them, that you've given the card and any
internal device whatever SCSI ID numbers the documentation
says they have to have, and that you have added the
daisy-chain termination out on the last device if it's
not self-terminating. Phew!
I've not seen the rear end of a Zip Plus yet, and I
don't know what the deal is with how it does both
SCSI and parallel together. That ignorance on my
part pretty much prevents me from helping you further
in any authoritative way. Frankly, though, if the
cable you ordered by calling 1-800-my-stuff doesn't
do the trick, I certainly think you have every right
to call them back, complain indignantly, and insist
that THEY resolve the problem. I can't believe that
the outfit/phone-number supplied by Iomega itself
is clueless about which cable is needed to connect
a Zip Plus to an ISA Jaz Jet SCSI card. Among other
things, ask them if you have to stay wedded to the
cable that came with the Zip Plus. I'm not sure
that's true. It may be that Iomega says that because
there are lots of cheapo SCSI cables out there that
can compromise the integrity of your data transfer
along the daisy chain, and that you need that cable
if the Zip is going to be connected to a parallel
port, to allow the Zip Plus to figure out that
indeed that's what it's connected to. At least
that's my guess for why the documentation is written
the way you say it is.
It sounds like the Mac ribbon-cable work-around may
work for you, too, but of course it's a kludge, and
since you've already ordered that inappropriate cable
from the my-stuff number, why not call them back, on
their nickel, and insist that they make good on what
was obviously THEIR mistake?
And of course, please report back to all of us here
about how it comes out, so we'll all then be able to
help out the next person we encounter with the same
problem. In the meantime, though, if you want more
advice from me, for what it's worth, why don't you
do it off-thread via carroll@rpi.edu to avoid additional
clutter here. You can summarize the whole ordeal to folks
once the saga has a happy ending.
My guess is that, once you've got the problem licked
and your Zip Plus is zipping right along, you'll quickly
forget the headaches. I did.
Just for the record: SCSI is high-capacity, but as far
as the end consumer is concerned, it sucks bigtime. This
cabling/daisychain nonsense must be a fatal killer for
all those folks out there who can't stop their VCR clocks
from blinking 12:00 at them. If you're not one of them,
and instead you get off on this kind of stuff, then
you might want to check out Peter M. Ridge, _The Book
of SCSI: A Guide for Adventurers_.
Happy Thanksgiving anyway.
Cheers, Tom (long IOM) |
