A new device naming scheme
Posted Apr 12, 2004 20:48 UTC (Mon) by
Peter (guest, #1127)
In reply to:
A new device naming scheme by X-Nc
Parent article:
A new device naming scheme
This issue can't be a Linux only issue. What are other OSs
doing?
AIX has a dynamic /dev created by userspace during boot. Similar to
udev, conceptually. Hard disks get named hdisk0, hdisk1, etc.
in the order they are detected; after initially being detected by the
system, their UUID or something is stored in a registry (the ODM) so that
they always get the same identifier thereafter. (This persistence of names
is not even all that important for disks, since AIX almost always uses disks
via its LVM, which has no need to care about device IDs since it uses its
own superblocks.)
So, AIX remembers all the devices it has ever detected on your system -
or been told about via /sbin/mkdev. Devices it has successfully
initialised are put in the available state, which involves creating
the device node in /dev; devices which were not detected are put in the
defined state, where device nodes in /dev are not automatically
created. Major numbers are assigned dynamically, I think even for core
stuff like /dev/null. And if you want to purge old entries from its
database for stuff you no longer have plugged in, you have to do this
manually, with /sbin/rmdev -d.
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