Here goes=
in struct bufferhead { } there are two kind of fields for device:
b_dev and b_rdev.. b_rdev is (in comments) said to be the "real" device
(whatever this means) b_dev has a comment saying that when it's equal to
B_FREE( current value 0xffff) the bufferhead is free. However when I list
the current buffer contents I get a lot of entries with b_rdev equal to 0
and b_dev!=B_FREE. So what is this device 0 ? One of previous answers
suggested that the 0 device is kernel's equivalent of NULL pointer, but
now I think it is not.. Here is an example of such :
anua:/proc/103/fd# ll
total 0
l-wx------ 1 anya users 64 Aug 25 16:52 1 -> [0304]:244877
l-wx------ 1 anya users 64 Aug 25 16:52 2 -> [0304]:244877
lr-x------ 1 anya users 64 Aug 25 16:52 0 -> [0304]:236684
lrwx------ 1 anya users 64 Aug 25 16:52 5 -> [0000]:785
(103 is kaudioserver)
You see that the last file descriptor points to inode on device 0.
You can also find a lot of such inodes if you look in the entry corresponding
to Xserver..
So what are they ? Are they sockets ? Are they buffered ?
thanks
Vladimir Dergachev
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