Messages in this thread | | | From | (david parsons) | Subject | Re: SCSI disk naming | Date | 10 Jul 1997 23:55:30 -0700 |
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In article <linux.kernel.xonyb7eq5ty.fsf@twins.iconsult.com>, Frohwalt Egerer <froh@twins.iconsult.com> wrote: >psj@cgmlarson.com (Patrick St. Jean) writes: > >[ SCSI 'first come first served' numbering ] > >> if it would be easily changable, and a couple of aspirins later am >> writing this. It seems to me that it would be a Good Thing to have >> something like /dev/sd0a (scsi disk, id 0, first partition). Then if a >> disk gets removed for whatever reason, there are no worries. > >This topic has been beaten to death here: > > - The kernel dev_t currently is too small to allow for this scheme.
Unless you do tricks with it.
The max major number is 128, and the allocated numbers (as of 2.0.28) don't go above 61. If you build the new majors 128+0 ! scsi disk 128+32 ! scsi tape 128+64 ! scsi cdrom 128+96 ! scsi generic
that leaves 13 bits for minor devices. Rest assured you will have to do some jumping through hoops to deal with these properly in the kernel, but 13 bits gives you 4 bits for ID, 3 bits for LUN, 3 bits for partition, and 3 bits for controller; I'm sure there are some systems out there that exceed these limits, but I suspect this won't describe the vast majority of the Linux machines out there.
____ david parsons \bi/ Not waiting for godot. \/
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