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FIZ(1) (Jan 31, 1988)) FIZ(1)
NAME
fiz - analyze damaged zoo archive for data revovery
SYNOPSIS
fiz
archive[
.zoo
]
DESCRIPTION
Fiz
is used to analyze damaged
zoo
archives and locate
directory entries and file data in them. The current
version of
fiz
is 2.0 and it is meant to be used in
conjunction with
zoo
version 2.0.
Fiz
makes no assumptions
about archive structure. Instead, it simply searches the
entire subject archive for tag values that mark the
locations of directory entries and file data. In a
zoo
archive, a
directory
entry
contains information about a
stored file such as its name, whether compressed or not, and
its timestamp. The
file
data
are the actual data for the
archived file, and may be either the original data, or the
result of compressing the file.
For each directory entry found,
fiz
prints where in the
archive it is located, the directory path and filename(s)
found in it, whether the directory entry appears to be
corrupted (indicated by [*CRC Error*]), and the value of the
pointer to the file data that is found in the directory
entry. For each block of file data found in the archive,
fiz
prints where in the archive the block begins. In the
case of an undamaged archive, the pointer to file data found
in a directory entry will correspond to where
fiz
actually
locates the data. Here is some sample output from
fiz
:
****************
2526: DIR [changes] ==> 95
2587: DATA
****************
3909: DIR [copyrite] ==> 1478
3970: DATA
4769: DATA
****************
In such output,
DIR
indicates where
fiz
found a directory
entry in the archive, and
DATA
indicates where
fiz
found
file data in the archive. Filenames located by
fiz
are
enclosed in square brackets, and the notation "==> 95"
indicates that the directory entry found by
fiz
at position
2526 has a file data pointer to position 95. In actuality,
fiz
found file data at positions 2587, 3970, and 4769.
Since
fiz
found only two directory entries, and each
directory entry corresponds to one file, one of the file
data positions is an artifact.
Once the locations of directory entries and file data are
found, the
@
modifier to
zoo's
archive list and extract
commands can be used and the archive contents selectively
listed or extracted, skipping the damaged portion. This is
further described in the documentation for
zoo
(
1
).
In the above case, commands to try giving to
zoo
might be
x@2526,2587
(extract beginning at position 2526, and get
file data from position 2587),
x@3090,3970
(extract at 3090,
get data from 3970) and
x@3909,4769
(extract at 3909, get
data from 4769). Once a correctly-matched directory
entry/file data pair is found,
zoo
will in most cases
synchronize with and correctly extract all files
subsequently found in the archive. Trial and error should
allow all undamaged files to be extracted. Also note that
self-extracting archives created using
sez
(the Self-
Extracting
Zoo
utility for MS-DOS), which are normally
executed on an MS-DOS system for extraction, can be
extracted on non-MSDOS systems in a similar way.
SEE ALSO
zoo(1)
BUGS
Random byte patterns can occasionally be incorrectly
recognized as tag values. This occurs very rarely, however,
and trial and error will usually permit all undamaged data
to be extracted.
DIAGNOSTICS
Fiz
always exits with a status code of 0.
FUTURE DIRECTIONS
Automation of data recovery from a damaged archive is
potentially achievable. However, since damaged archives
occur only rarely,
fiz
as it currently stands is unlikely to
change much in the near future.
AUTHOR
Rahul Dhesi