1 Feb
2023
1 Feb
'23
8:18 a.m.
On Jan 31, 2023, at 1:26 PM, David Glover-Aoki via
cctalk <cctalk(a)classiccmp.org> wrote:
On Jan 29, 2023, at 9:37 PM, Zane Healy via cctalk <cctalk(a)classiccmp.org> wrote:
So far I’ve tackled one split zip. I wasn’t having any luck with the version of PKZIP
that I assume created this. I copied the files into a directory, and did COPY
FILE1.ZIP+FILE2.ZIP+FILE3.ZIP+FILE4.ZIP+FILE5.ZIP COMBINED.ZIP
That still wasn’t working, as the file was corrupt, but I managed to use PKZIPFIX to fix
it, and then I could unzip it. The info above will definitely help, especially with
regards to the ZIPs missing the first part.
Slowly I’m recovering my old DOS system.
Zane
Some of the floppies I’m recovering data look to be either a multi-part ZIP file, or
something. Was this a separate product from PKZIP? I’m not sure if I have a copy of
PKZIP in the stuff I’ve recovered thus far. I’ve not pulled them into DOSBOX to try and
restore them, so far I’ve just tried to use Stuffit-Expander. Part of the problem is
every file has the same name, just on different floppies.
Info-ZIP still supports "split" archives, and spanned archives can be converted
to split archives by renaming them to the appropriate extension. From the man page:
zip version 3.0 and later can create split archives. A split archive is a standard zip
archive split over multiple files. (Note that split archives are not just archives split
in to pieces, as the offsets of entries are now based on the start of each split.
Concatenating the pieces together will invalidate these offsets, but unzip can usually
deal with it. zip will usually refuse to process such a spliced archive unless the -FF
fix option is used to fix the offsets.)
One use of split archives is storing a large archive on multiple removable media. For a
split archive with 20 split files the files are typically named (replace ARCHIVE with the
name of your archive) ARCHIVE.z01, ARCHIVE.z02, ..., ARCHIVE.z19, ARCHIVE.zip. Note that
the last file is the .zip file. In contrast, spanned archives are the original multi-disk
archive generally requiring floppy disks and using volume labels to store disk numbers.
zip supports split archives but not spanned archives, though a procedure exists for
converting split archives of the right size to spanned archives. The reverse is also
true, where each file of a spanned archive can be copied in order to files with the above
names to create a split archive.
A split archive with missing split files can be fixed using -F if you have the last split
of the archive (the .zip file). If this file is missing, you must use -FF to fix the
archive, which will prompt you for the splits you have.
David.