At 00:05 1/15/2000 , Brad Loomis wrote:
>In answer to some previous questions, the drives are seen in the Adaptec
>Bios scan as well in the SCSI set up. The Bios version is 1.34.3. I am
>using
>the two fan Bay Cooler from PC Power & Cooling. The Granite cable is
>18" to
>first drive, with two 12" segments following. I use a power plug right off
>the supply. I used individual power plugs off the supply when I did
>have all
>three installed, so as to have the HD as the only load. So in
>conclusion, I
>am not having any luck in being able to get this up and running. As I said
>before I did have the IBM running fine in conjunction with an IDE WD
>drive.
>I should also note as an after thought, I do have a 50 pin cable
>running to
>an internal Zip then out through the back plane to a scanner. The external
>68pin connector of the host is empty as is required.


Hi Brad

You didn't mention the Zip drive and scanner. Your total
cable length is waaaaay too long.

Your SCSI bus starts at the scanner and goes to the Zip
disk and then to the Adaptec controller and then to the
three hard drives. This is one SCSI bus and the length
of the bus is the total of the lengths of all the cables.

In my thinking, the 68 pin cable to your hard drives is
3.5 feet long and the 50 pin internal cable is at least
2.5 feet long and the external cable to your scanner is
probably at least 3 feet long (or maybe even 6 feet).

Thus your total cable length is at least 9 feet...probably
more. You are WAY over the 5 foot limit. With 5 devices
connected to your adaptec controller, even the most liberal
interpretation of maximum length is going to be 5 feet.
(Check Adaptec's installation guide. If you don't have it,
you can download the installation guide from
<http://www.adaptec.com/support/overview/aha2940uw.html>.

The other problem (and this one may be even worse) is
that you appear to be using the scanner to terminate the
external part of the SCSI bus. (You didn't say if you
are using a separate Active terminating module plugged
into the scanner.) The scanner will have a passive
terminator on board and you cannot use a passive terminator
ANYWHERE on your SCSI bus if you have Fast or Ultra hard
drives. (Also, I wouldn't use the termination in a Zip
drive either. I doubt it is good enough to use at Ultra
speeds.)

I cannot emphasize this too much. Pull the 50 pin cable
off the Adaptec controller (make sure that the Adaptec's
termination is set on AUTO) and see how your hard drives
work. (You may need to FDISK them again.)

If the drives work when you only have one cable connected
to the 2940UW, you are going to have to either lose the
Zip drive and scanner permanently or get another SCSI
controller just for these two devices. I'll also mention
that most scanner cables are cheaply made. They are just
good enough to use at the slow speeds that scanners use
to transfer data. Look at how much a Granite Digital
external cable costs...almost as much as the price of
your average scanner. No way your average scanner will
come with a cable that should be used on a SCSI bus with
Ultra hard drives. (Not that you would do so considering
the cable length issue.)

Lastly, your SCSI BIOS version 1.34.3 is a good one. No
problems there.

Regards,
Bill

            Do you want to signoff PCBUILD or just change to
                    Digest mode - visit our web site:
                    http://nospin.com/pc/pcbuild.html