This provides basic repair capabilities for damaged zip files. It scans the input file for the individual header-blocks of each contained file. If it finds a valid header-block, it attempts to read the appropriate data. If the data appears to be valid, it is written to the output file. It continues to scan until as much data as possible is recovered.
- The input file is unaltered.
- Minor information such as file attributes and comments may not be recovered.
- If an embedded zip file is found to be corrupt, there is still a good chance that some of its contents will be recovered (into the main directory of the archive).
- Data can be recovered from self-extracting archives without difficulty.
- Valid information from the existing central directory will be used in the new file (e.g. file attributes and comments) unless the box labelled Ignore central dir is ticked. (Only tick this box as a last resort.) Indeed, if no faults are found, the output file will typically be identical to the input file (although the order in which files appear in the central directory of the output file is guaranteed to be that in which the files are stored in the archive).
This applet can also assemble fragmented archives either from hard disk or from floppy disk.
- When reading from a floppy disk, the file name on each disk must be the same and the volume label on each disk must be PKBACK# 001, PKBACK# 002 ...etc.
- When reading from a hard disk (or network, cdrom, etc.) all files must be in the same directory.
Any sensible number sequence will be accepted
e.g. Archive001.zip, Archive002.zip ...etc.
e.g. MyDocs.Z01, MyDocs.Z02 ...etc.
- Files are concatenated and the directory structure fixed in a single process.
- If the process fails, you may try using the repair function (on the concatenated files - see below.)
Handling fragmented zip archives manually
The following instructions should be sufficient to understand how to deal with fragmented archives manually.
How to copy each part to diskette from a hard disk
- Ensure that file names adhere to the convention below.
'Test001.zip', 'Test002.zip', 'Test003.zip'
- Open a DOS window. Copy each file to it's own diskette. Rename it and relabel the diskette using
the following commands
Copy Test001.zip A:\Test.zip
Label A: PKBACK# 001 [Note the space between # and the first digit]
[Change diskette - place empty formatted disk in drive]
Copy Test002.zip A:\Test.zip
Label A: PKBACK# 002 [Note the space between # and the first digit]
How to assemble a fragmented archive into a single file.
- Open a DOS window enter the directory containing the files TestXXX.zip
- Concatenate them with the following command :-
Copy /B Test001.zip+Test002.zip+Test003.zip Test.zip
[Note the use of the /B switch - this is vital]
- Fix the internal directory structure using a ZipFix program.
e.g. ZipFix Test.zip
- Rename the resulting file if necessary. This is now a normal zip file and should be at least 4 bytes smaller than the sum of the parts.