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SubjectRe: Getting past the 16-bit dev_t limitation.
Matt Yourst wrote:
> >
> >I am working on a project that is going to find the current limit of
> >16-bits for device numbers to be a pain. While looking around in the
> >linux-kernel archive, ...
> >
> This is the whole reason Linux 2.4 uses devfs (device filesystem) -
> there is no need to use device numbers; you just register the name in
> the /dev/whatever namespace and it's done. (The kernel will assign a
> unique old-style 16-bit number for compatibility purposes as needed.)
> See linux/Documentation/filesystems/devfs/README for the full story.
> - Matt Yourst


Maybe I'm missing something, but I cannot find anything in the
2.4.0-test7 source which uses the DEVFS_FL_AUTO_DEVNUM flag; so it
looks to me like all drivers are currently running with their old-style
majors and minors. (I assume because there are applications out there
that depend on them.) I don't deny devfs has the potential to do away
with old style device numbers and their problems, but it does not seem
to be currently used in that manner. At least some new drivers can
presumably be written to take advantage of this feature since they may
not have to worry about application compatibility.

Anyway, one of the things I was hoping to find out by going to
linux-kernel was if there was anything other than devfs in the offing:
such a larger dev_t. So if anyone wants to chime in on things other than
devfs, I'd certainly like to hear about it.


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