Zip file testing errors
klitos last edited by
This is a detailed explanation of the problems with the Test action I referred to in an earlier post.
To illustrate the problems, I have attached two zip files.
The archive crc.zip contains three text files: one.txt, two.txt and three.txt. Each of them has a CRC error (I have manually corrupted the compressed data inside the zip file, to simulate typical corruptions in zip files such as those caused by serial-port transmission errors, floppies subjected to magnetic fields, cosmic rays, nuclear explosions, or whatever ;-)).
When you test this file in PowerArchiver, it will tell you about the CRC error in the first file, but, even if you choose to continue checking, it will not tell you about the errors in the other two files. Your rival archive utilities tell you about the errors in all three files.
The second archive, dcl.zip, contains a text file compressed with PKZIP’s DCLImpode algorithm. PowerArchiver is unable to extract it. That’s OK, it’s not a mainstream zip method. But what is definitely wrong is that PowerArchiver is silent about this file when you try to extract it; and, when you try to test it, it reports that there are no errors. In comparison, other archivers behave correctly by saying that they do not recognise this compression method.
thanks - we will check it out.