SCSI problems

[Robert Jennings]

On 8/4/03 1:35 PM, in article

I am having major problems with our G3 server. I was having problems with
our CDR drive and wanted to check it on another machine - anyway put it back
and now can't mount any SCSI external disk!?!?! All ID's were checked & all
terminated.

You don't want all of your SCSI devices terminated. Only the 1st and last
device need termination. The first device is usually the internal HD and it
is already terminated in the controller card, so just make sure the last
device on the SCSI chain is terminated.

[Bob Wardrope]

Post by Robert Jennings
On 8/4/03 1:35 PM, in article

I am having major problems with our G3 server. I was having problems

with

Post by Robert Jennings

our CDR drive and wanted to check it on another machine - anyway put it

back

Post by Robert Jennings

and now can't mount any SCSI external disk!?!?! All ID's were checked &

all

Post by Robert Jennings

terminated.

You don't want all of your SCSI devices terminated. Only the 1st and last
device need termination. The first device is usually the internal HD and

it

Post by Robert Jennings
is already terminated in the controller card, so just make sure the last
device on the SCSI chain is terminated.

This is the case, it's terminated at the end but just want to work
again..think that I have corrupted a preference file or something......

Hi.

Does Apple System Profiler see the SCSI card??

Bob W

[David C.]

Post by Robert Jennings
You don't want all of your SCSI devices terminated. Only the 1st and
last device need termination. The first device is usually the
internal HD and it is already terminated in the controller card, so
just make sure the last device on the SCSI chain is terminated.

Half right.

You need to terminate the two ends of the bus. If you have both
internal and external drives, then one end is the end of the internal
cable and the other end is the end of the external cable.

If you have only internal devices, then terminate the drive at the
end of the cable (or the end of the cable itself) and the host
adapter (which may be your motherboard.)

If you have only external devices, then terminate the drive at the
end of the cable and the host adapter.

If you have both internal and external, then terminate the drive at
the end of each cable and do _NOT_ terminate the host adapter.

Many host adapters are designed to detect this situation and
automatically turn internal termination on or off as required. But
some don't, and some that claim to don't work properly. There is
usually a way to override any automatic termination features, but the
mechanism will be specific to your host adapter. (The Adaptec card
in my PC has a ROM program that is activated by typing CTRL-A during
the boot sequence. I don't know what the usual mechanism is for Mac
adapters.)

-- David