#1357 7za a does not add "Packed" info

open
nobody
None
5
2013-06-29
2013-03-29
Mike
No

On Windows I use:

7za a "\bla\example.mysuffix" "\bla\source*"

This creates the ZIP file, but the Packed column shows 0 for all files (e.g. in WinRAR). Creating the ZIP with Windows File Explorer or WinRAR it shows the packed file size, which I think is as expected.

This seems to be the latest stable version of 7za (9.20.0.0, x64), from:

http://downloads.sourceforge.net/sevenzip/7z920-x64.msi

Discussion

  • Mike
    Mike
    2013-03-29

    P.S.:

    • SourceForge changed my "\\bla to "\bla in the above (it takes 3 to make 2...)
    • By "latest" I mean as linked to at the top of http://www.7-zip.org.
     
  • Mike
    Mike
    2013-04-15

    My mistake: as the example illustrates, since the command was missing the -tzip option, the archive was not ZIP but 7z. The Packed attribute works well with ZIP. I don't know if this is also a feature of 7z, or why WinRAR shows it as "0z".

     
  • Shell
    Shell
    2013-06-29

    It is a feature rather than a bug. 7-Zip stores packed size only for solid blocks, which is simpler than calculating the size of each file (this size may not even be integer!). Calculating each file's packed size on-the-fly is rather inefficient, so the block's size is displayed as the packed size of the first file in the block, and the other files should have this field empty (because their sizes are unknown). Again, for the sake of simplicity, zeros are shown instead of empty fields. So, the Packed column shows 0 for all BUT ONE file, and that file often looks like overgrown after compression. When solid archiving is disabled (which is always the case for the ZIP format), each block contains a single file and the Packed column is populated with the real data.

    WinRAR, by contrast, stores the packed size for each file in the archive. It therefore can display the compression ratio for each of the files.