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    SubjectRe: SCSI disk naming
    In article <>,
    Frohwalt Egerer <> wrote:
    > (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.

     \ /
      Last update: 2005-03-22 13:39    [W:0.019 / U:39.528 seconds]
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