fdformats(SMT)                 6 January 1993                 fdformats(SMT)


 Name

    fdformats - fit file archives onto floppies

 Syntax

    fdformats format volhdr filhdr volblk filrnd [+] [/] [type [size]]...

 Description

    An fdformats file describes a file archiving format to fdfit(SMT).  fdfit
    only understands distributed dictionary archives, such as tar(C),
    cpio(C), and ar(CP).

    Each line in an fdformats file describes a separate format.  Empty lines,
    and lines beginning with ``*'', are ignored.

    The first field, format, names the archive being described.  format is an
    alphabetic name; no digits or non-letters are allowed.

    The next four fields are decimal numbers giving the critical values:

    volhdr  overhead for each volume (floppy).  This is the sum of the sizes
            of the volume header and trailer blocks.

    filhdr  overhead for each file (element) in the archive.  This is the sum
            of the sizes of the element header and trailer blocks, and may be
            dependent on the length of the file's name.  If so, a ``+''
            should be specified in the miscellaneous fields section at the
            end of the line.

    volblk  volume blocking factor.  The number of bytes written to each vol-
            ume is always a multiple of this size.

    filrnd  file rounding boundary.  Each element in the archive, with its
            header and trailer, is rounded up to the next such boundary.

    Each of these values may have a suffixed unit of ``w'', ``b'', or ``k'',
    indicating multiplication of the number by 2, 512, and 1024, respec-
    tively.

    In addition, each number may be prefixed by ``#''.  This causes the num-
    ber suffixed to format, as specified by the user with the -fformat flag
    to fdfit, to be used instead of the value given in fdformats.  If the
    value in fdformats is suffixed with a unit, the value from -fformat is
    multiplied as indicated, ignoring any unit the user specified.  But when
    fdformats does not indicate a unit, any unit indicated with -fformat is
    used.

    After the four values is a miscellaneous information section.  If this
    contains a ``+'', then the length of a file's name must be added to that
    file's filhdr.  A ``/'' says that absolute pathnames are not a problem in
    this format.

    The other fields in the miscellaneous section are a single character type
    optionally followed by a size value.  type indicates that a special file
    is correctly saved in a format archive:

        b   block special device

        c   character special device

        d   directory

        n   name space entry, such as semaphores and shared data regions

        p   named pipes (FIFO's)

        &   links to previously saved files

    If size is a number (which may have a unit suffix), the type special file
    is always saved as if it were size bytes long.  A size of ``#'' uses the
    actual file size obtained from stat(S).  Otherwise, when no size is
    specified, zero (0) is assumed; the special file is completely described
    by the element header and trailer blocks.

 Notes

    Unpredictable results happen when both ``+'' and ``&'' are specified.

    The meaning of ``/'' is subjective; most archiving programs archive abso-
    lute pathnames, but the behavior on extraction is undesirable (extreme
    measures like chroot(C) must be employed).

    This is version 2.1 of the manual page, and describes the fdformats file
    expected by version 2.2 of fdfit.

 See also

    ar(CP), cpio(C), dd(C), fdfit(SMT), stat(S), tar(C)