Re: PATCH: cdrecord: avoiding scsi device numbering for ide devices

[Paul Jakma]

On Sat, 7 Aug 2004, Joerg Schilling wrote:

> 5)	Take a look at /etc/path_to_inst and call "man path_to_inst"

The irony here is that the kernel you point at does *not* try to map 
unrelated busses into the same namespace, that the tools and files 
like path_to_inst exist precisely to deal with the fact that topology 
information is no more than ephemereal, and that even the end-user 
device naming does *not* try to map IDE into SCSI.

That the /dev/dsk names typically encode some *logical* topology 
information into the names is beside the point, it's just the Solaris 
convention, the real point is that they abstract the device location, 
so that the user is not required to know that their disk is really 
at, eg:

	/devices/pci@0,0/pci-ide@7,1/ide@1/sd@0,0:d,raw

Which is where the /dev/ node would symlink to. The /dev/ name has 
nothing to do with physical topology (though might be vaguely 
similar). Also note that the logical /dev/ symlink name is encoded 
*differently* for IDE versus SCSI. Trying to plaster SCSI notations 
into IDE topology is just not useful. Indeed, some devices are not 
dependent on topology at all, they depend on some other topology 
independent identifier, eg FC UUID.

Having user utilities try invent their own namespace, inconsistent 
with both the physical topology and the system's conventions is even 
less useful.

regards,
--
Paul Jakma	paul@xxxxxxxx	paul@xxxxxxxxx	Key ID: 64A2FF6A
Fortune:
QOTD:
	"I drive my car quietly, for it goes without saying."
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/