Subject: Re: Another changer, another changer problem
To: None <current-users@netbsd.org>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
List: current-users
Date: 10/04/1998 08:54:06
> The SPARCs have the potential to find and configure in if you probe a
> device previously marked as "unconfigured", and they have the means
> as well to drop a previously but no longer configured device.

NetBSD/sparc has the former but not the latter, at present (see
SCIOCREPROBE); any SCSI system potentially has both.  I've used
re-probe capability not infrequently to hot-add a device to a system
(L1-A the system to freeze the SCSI chain, add the device, continue,
reprobe).  I've also hot-removed devices, but re-probe doesn't remove
them from the kernel's tables.  However, provided I don't attempt any
I/O while the device is disconnected, I've found I can add it back
later and it Just Works.  I've pondered trying to make reprobing remove
devices that aren't there, but so far haven't actually even looked at
what would be necessary in the code.

					der Mouse

			       mouse@rodents.montreal.qc.ca
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