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SubjectRe: IDE-Floppy and devfs
Hello Paul,

(you CC'ed your original post to vger.rutgers.edu, I shamelessly corrected
this for this reply)

> I have (finally) merged your patch in with the ide-floppy driver and
> have it working with devfs here on my laptop for a PCMCIA Clik drive.

Have you merged my patch in literate or in sense? If the first, I hope you
looked over it, I am not at all convinced that it does the right thing (TM).

A remaining problem was for me that the part4 entry for my ZIP disks was not
created unless a disk was in during module loading time. For sure, this COULD
be done by just faking a part4 entry in the ide-floppy code, which then would
eventually create a duplicate entry, when the disk layer finds the medium.

I think the right thing (TM) would be to give the block device layer a chance
to know that the medium has changed, when a disk is inserted, which would
then rescan the partition table and create the corresponding entries. The
driver should give the block layer the needed info for that, and eventually
create further links, as in /dev/ide/fd/... and so on. (see below for more on
that)

I'm not sure if this is possible, but I'd prefer this solution - I just don't
know what others think of it.

The same thing could eventually be done for CD-ROM or even normal floppy
disks. I like the approach very much, which would make it possible to use
devices in a MacOS-like way - just insert the disk, kernel does what it needs
to to notify userspace of that event, userspace creates the nifty icon on my
desktop. Ok, ok, I know I'm biased... :-)

> Sorry it took so long but I had to learn the entire 2.4 module stuff,
> PCMCIA stuff, and devfs stuff in my spare time, which there wasn't
> enough of.

No problem, my spare time is limited too so I know this problem too well :-)

> A question. It says in Richard's devfs documentation that the
> ide-floppy driver should create device names under /dev/ide/fd/...
> (similar to /dev/ide/hd/...). However, looking through the code I am
> under the impression that this should actually take place in devfsd. Am
> I right, or am I crazy? Are there any of the devfs experts with an
> ATAPI ZIP/LS-120 drive that can check what I have done?

I think the ide-floppy driver should do, because it KNOWS it is a floppy
driver. devfsd doesn't necessarily know that
/dev/ide/host0/bus0/target1/lun0/disk is really an IDE floppy disk - it might
be a hard disk, as well, or anything else. The driver knows so, and should
therefore create the link withour requiring further configuration on the user
side, because the idea of this links is to have access to the devices without
having to scan the entire bus structure. And this is supposed to work even
without devfsd, I dearly hope so...

> BTW, now I finally understand it, I really like devfs. I just need to
> get rid of all those extra tty devices in /dev and I'll have a nice
> clean /dev that actually makes sense. Good work guys.

I like it very much too, and can't appreciate to see it in all its beauty
when all the ugly peculiarities have been hacked out and the drivers have all
been adapted to work just fine... it's really a great idea!

Greetings,
Andreas

--
->>>----------------------- Andreas Franck --------<<<-
---<<<---- Andreas.Franck@post.rwth-aachen.de --->>>---
->>>---- Keep smiling! ----------------------------<<<-
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