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

Paul Jakma
2004-08-08T04:08:34Z

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@clubi.ie paul@jakma.org Key ID: 64A2FF6A
Fortune:
QOTD:
"I drive my car quietly, for it goes without saying."