Main Area and Open Discussion > General Software Discussion

How to repair zip files?

<< < (4/4)

Renegade:
@Edvard: Those were anomalous instances and not repeatable. I could be wrong, of course, but that's what I was trying to point out in my earlier comment - i.e., that this thread is about something (an error or a fix for an error) that doesn't happen under normal circumstances, or isn't actually required, and which couldn't be mitigated or repaired if it occurred anyway.

In other words, there is likely to be no need to repair .ZIP files, as you would probably only get damaged ZIP files from an irreversible anomalous and non-repeatable) event, and due to the simple structure of .ZIP files, you will be unlikely to be able to recover/repair/reconstruct the lost/corrupted data - you couldn't "magic" the data out of nowhere.
-IainB (September 19, 2014, 09:03 AM)
--- End quote ---

IainB is right.

Compression relies on entropy (or many forms of compression anyways). This is a good site to get started on it:

http://www.maximumcompression.com

It's not been updated in a while, but it's excellent.

If a ZIP file cannot be recovered by the normal recovery mechanisms inside your compression software, it's unlikely that it can be recovered. Ever. Download again, or resign yourself to it being lost. The amount of effort to recover a corrupt file is likely not worth it.

If you want recovery capabilities, don't use ZIP compression.

Edvard:
@Edvard: Those were anomalous instances and not repeatable.
...
-IainB (September 19, 2014, 09:03 AM)
--- End quote ---

True, but I bet I could corrupt any Zip file real fast by unplugging my box while creating an archive :P

All kidding aside, WinZip's knowledge base describes a few ways that Zip files can be corrupted; accidents being far more common, but rogue archive software writing invalid or incomplete headers factor in as well.
http://kb.winzip.com/kb/entry/35/

Innuendo:
The zip file structure has always been....fragile. Consider using rar instead as it will give the option to store recovery records with the archive that will give one a much better chance of archive repair should something go wrong.

MilesAhead:
The zip file structure has always been....fragile. Consider using rar instead as it will give the option to store recovery records with the archive that will give one a much better chance of archive repair should something go wrong.
-Innuendo (September 21, 2014, 10:16 AM)
--- End quote ---

Are there any free ports of Linux lossless compression tools that may be robust on Windows?  I'm just curious.  A few searches didn't bring up anything germane.

Navigation

[0] Message Index

[*] Previous page