Name
I line
Synopsis
When a machine crashes under Unix, files in a directory can become detached from that directory. When this happens, those orphaned files are saved in a directory called lost+found. Because filenames are saved only in directories, orphaned files are nameless. Consequently, Unix stores them in lost+found using their inode numbers as their names.
To illustrate, consider finding these four files in lost+found after a crash:
#1528 #1200 #3124 #3125
Two of these are qf
files, and two are
df
files. Beginning with V8.7
sendmail, the qf
files
contain a record of the inode numbers for their corresponding
df
files. That information is stored in the
I
line:
Imajor
/minor
/ino
Here, the major
and
minor
are the major and minor device
numbers for the disk device that the df
file was
stored on. The ino
is the inode number for
the df
file. In our
lost+found example the following command could
be run to pair up the orphaned files:
% grep "^I.*/.*/" *
#1200:I123/45/3124
#1325:I123/45/1528
This shows that the qf
file
#1200 has the df
file
#3124 and that the qf
file
#1325 has the df
file
#1528.
The sendmail program does not check the inode
number in the I
line against the actual inode
number of the df
file. Instead, the
I
line is generated afresh each time the
qf
file is processed.
When df
, qf
, and
xf
subdirectories are used, and when those
subdirectories are on separate disks, a crash of one disk can leave
the df
or qf
file intact, and
the other in lost+found.
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