Unix |
Unix v6 |
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icheck(8) |
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icheck file system storage consistency check [ ] [
numbers ] [ filesystem ] examines a file system, builds a
bit map of used blocks, and compares this bit map against
the free list maintained on the file system. If the file
system is not specified, a set of default file systems is
checked. The normal output of includes a report of The
number of blocks missing; i.e. not in any file nor in the
free list, The number of special files, The total number of
files, The number of large and huge files, The number of
directories, The number of indirect blocks, and the number
of double-indirect blocks in huge files, The number of
blocks used in files, The number of free blocks. The flag
causes to ignore the actual free list and reconstruct a new
one by rewriting the super-block of the file system. The
file system should be dismounted while this is done; if this
is not possible (for example if the root file system has to
be salvaged) care should be taken that the system is
quiescent and that it is rebooted immediately afterwards so
that the old, bad in-core copy of the super-block will not
continue to be used. Notice also that the words in the
super-block which indicate the size of the free list and of
the i-list are believed. If the super-block has been curdled
these words will have to be patched. The flag causes the
normal output reports to be suppressed. Following the flag
is a list of block numbers; whenever any of the named blocks
turns up in a file, a diagnostic is produced. is faster if
the raw version of the special file is used, since it reads
the i-list many blocks at a time. Currently, /dev/rrk2 and
/dev/rrp0 are the default file systems. dcheck (VIII),
ncheck (VIII), fs (V), clri (VIII), restor(VIII) For
duplicate blocks and bad blocks (which lie outside the file
system) announces the difficulty, the i-number, and the kind
of block involved. If a read error is encountered, the block
number of the bad block is printed and considers it to
contain 0. ‘‘Bad freeblock’’ means
that a block number outside the available space was
encountered in the free list. ‘‘n dups in
free’’ means that n blocks were found in
the free list which duplicate blocks either in some file or
in the earlier part of the free list. Since is inherently
two-pass in nature, extraneous diagnostics may be produced
if applied to active file systems.
It believes even preposterous super-blocks and consequently
can get core images.
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icheck(8) |
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