Zip files
Starting with version 2.00, either the Source
or the Target directory (but not both) may be
replaced as storage location by a compressed file. Directory
Compare uses the popular zip format for
compressed files: they are useful to save space, but adding and
deleting files (as opposed to extracting files) takes time,
especially if an high Compression level (see Options) is used.
Since the main goal of Directory Compare is
to compare and synchronize directories, not zip files, and the
latter are not directories, they suffer some restrictions (apart
from being slower when adding and deleting files):
- At least one of Source and Target
must be a true directory. You cannot use Directory
Compare to compare and synchronize zip files
directly. (Of course, you can use it to extract one of
the zip files to a temporary directory and then compare
and synchronize this directory first with the second zip
file and then, if any update has been made to the
temporary directory, with the original zip file.)
- Some options apply only to zip files and are listed in a
separate sheet in the Options
dialog box.
- Items deleted from zip files are not sent to the recycle
bin, so the Delete... and Eliminate...
menus are equivalent when applied to zipped items.
- Since zipped items are not independent files, they cannot
be executed or viewed with the Open...
menus or double clicking on them with the right values on
the Options dialog box.
For the same reason, you cannot compare a zipped item
with a file with the External Compare program.
Of course, the program could extract the item to a
temporary location and execute it or launch the external
program with its file specification; but who would the
temporary file when it is no longer necessary?
- By default, when the Display icons
option is selected, an item that exists only in a zip
file (and not in a directory) will be assigned the
icon. However,
if you are ready to pay the time penalty, you may select
the If necessary unzip file to get its icon
option and the program will try harder to get the right
icon.
- Since apparently empty directories cannot be stored in zip
files, the List, Copy and Delete directories
option is ignored if either the Target
or the Source is a zip file, and
directories will not get separate entries in the main
list.
- If Short file names is selected files
will be stored in a zip file with its short name, but
already stored files will be listed with the name they
have in the zip file, because there is no reliable way to
predict the short name Windows will assign to them when
extracted to a disk.
- Aborting the adding or removing of items in a zip file
(which is sometimes necessary if a very long zip
operation has been inadvertently started) may lead to a
corrupted zip file. So, for security, you may want to
select the Backup zip file... option to
make sure that, at least, you do not lose the original
zip file. This is another reason to make sure that you
select your Temporary directory in your
bigger and faster disk.
- The code to manage zip files may issue error messages not
available with files in directories.