32v 1m icheck

ICHECK(1M) UNIX Programmer's Manual ICHECK(1M)

NAME

    icheck - file system storage consistency check

SYNOPSIS

    icheck [ -s ]  [ -b numbers ] [ filesystem ]

DESCRIPTION

    _I_c_h_e_c_k 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 _i_c_h_e_c_k includes a report of

         The total number of files and the numbers of regular,
         directory, block special and character special files.

         The total number of blocks in use and the numbers of
         single-, double-, and triple-indirect blocks and direc-
         tory blocks.

         The number of free blocks.

         The number of blocks missing; i.e. not in any file nor
         in the free list.

    The -s option causes _i_c_h_e_c_k 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 immedi-
    ately 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 -s option causes the normal output reports to be
    suppressed.

    Following the -b option is a list of block numbers; whenever
    any of the named blocks turns up in a file, a diagnostic is
    produced.

    _I_c_h_e_c_k is faster if the raw version of the special file is
    used, since it reads the i-list many blocks at a time.

FILES

    Default file systems vary with installation.

SEE ALSO

    dcheck(1), ncheck(1), filsys(5), clri(1)

DIAGNOSTICS

    For duplicate blocks and bad blocks (which lie outside the
    file system) _i_c_h_e_c_k announces the difficulty, the i-number,
    and the kind of block involved.  If a read error is encoun-
    tered, the block number of the bad block is printed and
    _i_c_h_e_c_k considers it to contain 0.  `Bad freeblock' means
    that a block number outside the available space was encoun-
    tered 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.

BUGS

    Since _i_c_h_e_c_k is inherently two-pass in nature, extraneous
    diagnostics may be produced if applied to active file sys-
    tems.
    It believes even preposterous super-blocks and consequently
    can get core images.