Re: Apple Hi-Speed SCSI Card

[dempson@atlantis.actrix.gen.nz (David Empson)]

In article <1995Sep13.141222.1@surf.eng.yale.edu>,
 <wklye@surf.eng.yale.edu> wrote:
> I've been trying to set up a SCSI harddrive on my Apple //e.  It is a
> 80meg drive hooked to an Apple Hi-Speed SCSI card.  On attempting to
> partition the drive the the provided software, I am asked to select
> which drive to partition - even though I have only ONE drive (and
> nothing else on the SCSI chain).  Still the partition program
> indicates I have seven drives (drive numbers 0 to 7) on-line.

Are you sure that all eight IDs are listed, and not just seven of them?

This could be caused by a faulty drive or SCSI card, or the drive and
SCSI card being set to the same SCSI ID, or by improper termination of
the SCSI bus.

If you haven't changed the switches on the card, it defaults to ID 7
(switches 2, 3 and 4 DOWN), and there is rarely any need to change this.

Make sure the drive is not set to SCSI ID 7.  If it has an external ID
selector, it should be possible to change the ID to another value, and
see if the problem goes away.

If the drive doesn't have an ID selector, try changing the SCSI card
to a different ID.


Regarding termination: the drive must be terminated, either using
internal termination resistors, or with a clip-on terminator on the
back of the drive (but not both).

It is also necessary for at least one device (the computer or the
drive) to provide power for the termination.  Older Apple High-Speed
SCSI cards do not provide termination power.  Drives are highly
variable.  Recent models of Quantum drives always supply termination
power (my 240MB and 830MB drives both do), but I don't know about older
models or other brands.


If you have valid termination, and changing the ID has no effect, then
one of the devices or the cable may be faulty.
-- 
David Empson
dempson@actrix.gen.nz
Snail mail: P.O. Box 27-103, Wellington, New Zealand