>> If there is a safe way to do this, it usually involves Stop-A'ing
>> the kernel so there won't be any activity on the SCSI bus _while_
>> you're changing the connectors around, and then continuing it when
>> you're done.  (It's also a good idea to let the machine get quiet
>> and sync it first.)

This is what I've always done.

> I'm not sure all controllers can do this but the ncr53c8xx can put
> its SCSI lines in high-impedence by register settings.  A ioctl which
> could hang the scsi controller and disconnect it from the SCSI bus
> for a while would allow this kind of this in a safe way

Somewhere in the archives is a discussion on basically that subject.
As I recall, all that was concluded was that doing this with reasonable
generality was a Hard Problem.

> (I think the stop-A trick may have bad side effect if you halt the
> kernel in the middle of a disconnect/reselect transfer).

Out of all the times I've warm-plugged SCSI devices, *once* I've
crashed the machine, and I think this is exactly what happened - I
suspect I L1-Aed the machine in the middle of an operation (either
during I/O or between disconnect and reconnect).

					der Mouse

			       mouse@rodents.montreal.qc.ca
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