Adaptec 3944 Cannot See SCSI ID > 7

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We have an Adaptec 3944 host adapter in a Compaq 1850R, and that adapter
doesn't seem to be able to deal with any SCSI ID greater than 7, even though
the BIOS suggests it can see 15 IDs per channel. What would cause the
adapter to not see SCSI IDs 8 or higher?
 
Hi Will,
I'm going to make some assumptions here.
I assume you are jumpering Wide SCSI drives on a 68 or 80 pin cable
and know what you are doing by jumpering at least the 4th set of ID
jumper pins (ID8) in addition to whatever other jumpers are set.
I assume that each drive has a unique ID which none of the other
drives has.
I assume that you have the bus segment terminated correctly.
I assume you have gone into the SCSI card bios (ctrl A at the banner)
and used the controller bios to try and detect the drives.

You haven't really posted your configuration but.... try a single
drive with all the ID jumpers jumped (ID15) on your Wide cable.
(that is the 68pin cable - the 50pin cable is physically wider than
the 68pin cable but is not the Wide cable) and see if the 3944 bios
can detect it. Also, the card will not load the bios if there are no
bootable drives.

All things being equal.... I would suspect the cable.

However...you haven't given the entire model Adaptec SCSI controller.
The specs I bring up seem to point to the 3944 being a Differential
SCSI controller. Differential = HVD. HVD = High Voltage Differential
as opposed to the standard LVD drives.
HVD drives are used in electrically noisy industrial settings and a
standard plain vanilla LVD or SE or 50pin narrow SCSI drive will NOT
work on the HVD controller. And quite possibly never work again on
anything if it's been hooked to a HVD controller.
Is the actual model number of the card something like: AHA-3944AUWD?


We have an Adaptec 3944 host adapter in a Compaq 1850R, and that adapter
doesn't seem to be able to deal with any SCSI ID greater than 7, even though
the BIOS suggests it can see 15 IDs per channel. What would cause the
adapter to not see SCSI IDs 8 or higher?
Click to expand...
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Our setup is in fact HVD, going to a Tape Library. Tape libraries have up
until last year most commonly used the high voltage interface because they
were quite often physically separated by many feet from the hosts that used
them.

To summarize the elements: The Adaptec AHA-3944 is an HVD controller with
two VHCDI connectors on the back (yes, I do realize that this is quite a
rare connector type for HVD controllers, but it is what is there). The
VHCDI are cabled by a VHCDI and 68-pin Universal SCSI cable. In theory,
Universal SCSI should work with HVD, but I'm like you skeptical of the cable
at this point. We have thought about buying a VHCDI to 68 pin adapter and
attaching that to an old but thick 28 gauge wire HVD cable, and seeing if we
notice any difference.

The tape drives are in fact HVD SCSI, not LVD. I'm well aware that you can
damage device and/or controller by mixing HVD on either end with non-HVD.
The tape drives set their SCSI ID by a selector on the back of the tape
drive.

We tried a variation on your experiment already: we cabled directly to the
tape drive, and terminated with HVD terminators at the device. We then set
different SCSI IDs on the tape drive. As soon as we hit 8 or above the
device disappears from the chain. The Adaptec BIOS seems to suggest that
it can support 15 devices. The Adaptec BIOS does not see the device either
when you scan devices, if the tape drive is set to 8 or higher. So it is
not an OS issue.

--
Will

NOTE: To reply, CHANGE the username to westes AT earthbroadcast.com

Overlord said:
Hi Will,
I'm going to make some assumptions here.
I assume you are jumpering Wide SCSI drives on a 68 or 80 pin cable
and know what you are doing by jumpering at least the 4th set of ID
jumper pins (ID8) in addition to whatever other jumpers are set.
I assume that each drive has a unique ID which none of the other
drives has.
I assume that you have the bus segment terminated correctly.
I assume you have gone into the SCSI card bios (ctrl A at the banner)
and used the controller bios to try and detect the drives.

You haven't really posted your configuration but.... try a single
drive with all the ID jumpers jumped (ID15) on your Wide cable.
(that is the 68pin cable - the 50pin cable is physically wider than
the 68pin cable but is not the Wide cable) and see if the 3944 bios
can detect it. Also, the card will not load the bios if there are no
bootable drives.

All things being equal.... I would suspect the cable.

However...you haven't given the entire model Adaptec SCSI controller.
The specs I bring up seem to point to the 3944 being a Differential
SCSI controller. Differential = HVD. HVD = High Voltage Differential
as opposed to the standard LVD drives.
HVD drives are used in electrically noisy industrial settings and a
standard plain vanilla LVD or SE or 50pin narrow SCSI drive will NOT
work on the HVD controller. And quite possibly never work again on
anything if it's been hooked to a HVD controller.
Is the actual model number of the card something like: AHA-3944AUWD?


We have an Adaptec 3944 host adapter in a Compaq 1850R, and that adapter
doesn't seem to be able to deal with any SCSI ID greater than 7, even though
the BIOS suggests it can see 15 IDs per channel. What would cause the
adapter to not see SCSI IDs 8 or higher?
Click to expand...
~~~~~~
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root@localhost
postmaster@localhost
admin@localhost
abuse@localhost
postmaster@[127.0.0.1]
~~~~~~
Remove "spamless" to email me.
Click to expand...
 
Just came across this on a plextor website, and I remembered this post,
don't know if it has anything to do with your problem :

-------The SCSI-ID is a unique identification number assigned to each SCSI
device. Therefore each device must have a different ID number. The SCSI-ID
also determines the priority of the SCSI devices when two or more devices
want to use the SCSI bus at the same time. It's the device with ID 7 that
has the highest priority on the bus. This ID number is usually assigned to
the host adapter. The priority of other IDs is descending from 6 till 0.
So if you are using two or more devices on one SCSI adapter card you should
verify the ID configurations of all the devices and make sure they are all
different. -------

I don't have much experience with SCSI, but judging from this, I can't help
conclude that they are saying that one SCSI can only handle up to 7 SCSI
id's.
Maybe you just need to add another SCSI card, and continue using the ID's of
the devices on this card where the ID's of the other card ended.
Just a non-educated guess... Hope it can make some difference...

Glenn.

Rick said:
"CHANGE username to westes" <[email protected]> wrote in
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message news:[email protected]...
 
I am thinking that it might be a termination issue. check your card to see
if the interfaces are terminated at the controller or not.

yes, ID7 is usually the adapter itself. It might be that only 7 devices per
interface can be used, but when using the internal and external interfaces
at the same time, you can get your 15 devices (0 -15, -1).

NuTs
 
You are on drugs, right nutzy? All 15 devices are available on each channel.

| I am thinking that it might be a termination issue. check your card to see
| if the interfaces are terminated at the controller or not.
|
| yes, ID7 is usually the adapter itself. It might be that only 7 devices per
| interface can be used, but when using the internal and external interfaces
| at the same time, you can get your 15 devices (0 -15, -1).
|
| NuTs
|
 
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