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SubjectRe: Lots of SCSI-disks, how?!
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Richard Gooch <Richard.Gooch@atnf.CSIRO.AU> writes:

> Correct. We were just using 64 bits as an example.
> [...]
> I don't see how you could increase the size of i_rdev in the kernel's
> struct inode without breaking C library compatibility, since the
> library expects i_rdev to be 16 bits followed by i_size.

It is possible when all functions passing device numbers to the kernel
can fall back into 16bit mode. The major/minor/makedev macros would
always use the new format and the libc makes sure it works.

And I don't speak about splitting the device numbering. It's just
that some numbers are avoided withthe new numbering scheme and those
are recognized specially by the kernel.

> Also, I don't like the idea that libc 5 applications (like <fdisk>
> and other useful tools) cannot access the new devices/partitions.

Of course not. This will break in any case.

> Finally, I don't see how your scheme can work to support more SCSI
> minors. Unless you have a whole new SCSI driver on one of the "high"
> majors. Yuk. That gets back to the problem of "blocking" libc 5 access
> to some of your discs.

With libc5 you will never be able to change the device numbering. See
above, you agreed already. So the remaining question is how to keep
libc5 alive on new kernels which don't need many SCSI IDs etc, i.e.,
in situations which can be handled now.

-- Uli
---------------. drepper at gnu.org ,-. 1325 Chesapeake Terrace
Ulrich Drepper \ ,-------------------' \ Sunnyvale, CA 94089 USA
Cygnus Solutions `--' drepper at cygnus.com `------------------------

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