🚀 go-pugleaf

In article <PAISLEY.89May5100342@circus.cme.nbs.gov> paisley@circus.cme.nbs.gov
(Scott Paisley) writes:
>
>Can two macs access a single SCSI harddrive via hardware?  That is,
>partition the harddrive so that each mac has its own partition, and
>each mac would connect to one of the scsi connectors on the drive.
>Can this work?  What happens when both macs try to write at the same
>time?

Uh, 'fraid not.  The way the SCSI protocol/hardware is designed is that there
can only be one controlling device (ie. Macintosh) on a chain.

Quoting here from *Technical Introduction To The Macintosh*:
(great book, I highly reccomend it)

"When two SCSI devices communicate with each other, one acts as the initiator
and the other as the target.  The intitiator asks the target to perform a
certain operation, such as reading a block of data.  A SCSI device typically
has a fixed role...for instance, the Macintosh always acts as initiator....
Multiple initiators and multiple targets are allowed on a SCSI bus, but *only
one Macintosh computer can be connected to a SCSI bus at a time.*"

Since the two SCSI jacks on the back of your average hard drive form an
effective "SCSI Thru" combo, putting two Macs on one drive would certainly
confuse the hell out of everybody (both Macs have a SCSI id number of 7, so
you're screwed right there) and might very well damage the drive or the Macs'
SCSI chips.

So, two Macs & one drive is wack.  Don't do it.

-mike

#########################################################################
Mike Rose               "I hope that one or two immortal lyrics will come
mr2t+@andrew.cmu.edu     out of all this tumbling around."
Class of 1991 (I hope!)            -Poet Louise Bogan on her affair
Disclaimer: I work for a            with poet Theo Roethke
newspaper; they relish my opinions.