Hello all,
I use kernel 2.4.9 with devfs support, and installed devfsd too.
The fs is not mounted automatically, nor do I use the "only" option. I mount
the fs manually, often not on /dev, and experiment with things before I finally
dump the old /dev directory. I like the idea of devfs very much, but still have
a few questions:
I have read in the FAQ the following sentence:
"Also, because the devfs namespace exists without any devfs mounts, you can
easily mount the root filesystem by referring to an entry in the devfs
namespace."
1. I find it a little confusing or at least not conceptually clear that I have
to pass "root=/dev/ide/..." to the kernel even while the fs is not mounted
anywhere, and that /proc/mounts will show the root device mounted on
/dev/ide/... even though I might later mount the devfs to say /mnt/dev or to
several mount points, all different from /dev, if I please. In fact the current
setup suggests that the kernel mounts one single device node of the devfs tree
but nothing else. This is kind of a chicken and egg problem: to be able to
refer to the (root) device by node name (in order to mount it) you need the
node, for the node to exist, however, you need the filesystem, which in turn
needs the root device to be mounted. I would find it lots cleaner to be able to
say "root=ide/..." or "root_device=ide/..." instead.
2. Can I persuade the kernel to mount the fs at boot time to something other
than /dev?
3. Not strictly confined to devfs, but also to modutils, is this: If I compile
my kernel with some devfs-aware modules, then basically the module (say sg.o)
contains the information, what device node(s) it will implement (through
devfs_register(), which I cannot change without kernel patching). Still I have
to manually specify through a devfsd LOOKUP event and a modules.conf alias,
that a request for module /dev/scsi/.../generic will really mean a request for
module sg, although there is not a lot of other choices. I would appreciate
comments on this apparent duplication.
4. Is devfsd the only designed way to autoload devfs-aware modules? As I
understand it is the kernel-resident devfs code that detects the lookup event,
and devfsd only knows about it via the .devfsd communication channel, so
requesting the module would be simple without devfsd running, unless we want to
carry out some special action.
So much for today 8^) I'll keep trying to clear the picture, but any help would
be appreciated!
Marton
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