Re: Migrating to larger numbers

Raul Miller (rdm@test.legislate.com)
Tue, 8 Jun 1999 12:10:09 -0400

Richard Gooch <rgooch@atnf.csiro.au> wrote:
> However, for the sake of argument, let's say we write device drivers
> and make use of dynamic device numbers. I don't actually see where the
> problem is.

Ok, consider this scenario:

(1) Some application is using device files over NFS. [If this isn't
happening, there's no problem with 64 bit device numbers.] Let's use
your "exporting root to legacy machines" case...

(2) The system uses SCSI. [This is an example where 64 bit device
numbers might be good.]

(3) The NFS server gets taken down for a few minutes and disks get added
to it. [This is the case where the semantics of the device numbers
become significant.]

NFS semantics suggest that the application freeze while the server
is unavailable, and everything continue on after it comes back up.

-- 
Raul


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