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[SLUG] I hate udev!


Catchy Subject?

<rant emotion="annoyed" sanity="atrisk">

Yes I hate udev because if my server is rebooted and the tape drive isn't switched on then the entries in /dev/ such as nst0 don't get created. Then my backup fails or worse the disk is completely full because writing to /dev/nst0 when the device file doesn't exist creates a data file on the disk which grows to be bigger than the /dev partition. I don't want to reboot my server right now but I'd love to be able to do a backup. Is there a sane way to tell udev to create the entries for the device without rebooting?

In the "bad old days" when I was using System V you simply created the device file with mknod and that was it. Of course you had to know the major and minor numbers but that could be determined by the scsi address and once that was sorted it was straight forward.

Now in Linux figuring out what a device file's name and major and minor numbers should be appears to be some sort of sadistic guessing game devised by some manic kernel developer.

E.G. On SystemV

 Scsi: Channel 1, ID 2, partition 5  ==> /dev/rdsk/c1d2s5

But who could tell me what the device name would be on Linux?
Well that'd be a grand guessing game depending on what other devices you had attached / where turned on at the time you last rebooted the system. (which manic devised this concept? Linus? yeah thought so, he is crazy!)

Assuming I can find out what the major and minor numbers should be can I just use mknod to make the device permanent or will udev overwrite / delete it again?

Can I get rid of udev? Or will my disks evaporate in a puff of lost device files?
</rant>

Can anyone tell me what, if any, simple steps I can take to get my tape visible again without rebooting?
(Oh FC4 btw)


TIA's

Pete