+[8.50b1]Can't extract/test files from 50% of my 7z archives

Biozynotiker · Post by *Biozynotiker » 2013-08-28, 18:23 UTC

Can't extract/test files from 50% of my 7z archives
(Use archives as folders options is enabled)

Press Return on an 7z archive (created with 7zip V9.20),
it seems all archive content listed correctly,
but if I extract or press f3 on a file,
TC says "could not found file xy".

Testing such archives fails also, TC just do nothing, no error at all.

Because this doesn't happend with all 7z archives,
i have no clue if this was a "solid" archive problem or not.

I report more infos, if i had any....

*EDIT*
I seems to happend only, if the 7z archive has more than 1 blocks.
All files thats not on block 0, seems to be unaccessable.

Post by *ghisler(Author) » 2013-08-29, 13:36 UTC

How can I create such a multi-block 7zip file?

Biozynotiker · Post by *Biozynotiker » 2013-08-29, 15:04 UTC

ghisler(Author) wrote:How can I create such a multi-block 7zip file?

The easiest way is to use the "-ms=e" option.
(Use a separate solid block for each new file extension)

You can list archive content in a technical view by this command:
7z.exe l -slt archivename.7z

MVV · Post by *MVV » 2013-08-29, 15:44 UTC

I think such semi-solid archive may also be created with 7-Zip create archive dialog too, you just need to set middle block size (e.g. 1-2 MB).

Post by *ghisler(Author) » 2013-08-30, 16:01 UTC

Thanks, I will try that. I hope that the 7zip dll can handle this.

MVV · Post by *MVV » 2013-09-01, 08:46 UTC

I've tested built-in 7z unpacker with multi-block files:
1. Created by specifying '1MB' block size,
2. Created by using 7z.exe with -ms=e,
3. Created by adding new files to an existing solid 7z archive.

All theese contain more than one block (7-Zip GUI shows block number for every file in an archive).

TC was able to unpack all tested files completely (all blocks). Maybe there is another reason...

Biozynotiker,
Are your files encrypted? I think it would be useful if you provide some sample file of yours.

Biozynotiker · Post by *Biozynotiker » 2013-09-01, 09:55 UTC

After MVV's post, I'll tried to create such 7z archives, because the existing archives are a way to big to provide.

First I was failed to create such archives,
then I think about again, and found some similarities.
Now I'm pretty sure i found the problem.

TC fails on all archieves, that was created with a dictionary above 512mb (1GB in my case).
In techincal list view, there must be listed as LZMA:29 or LZMA:30 or PPMD:1024m or PPMD:30 or similar.

Note:
You'll need 11,5 * (Dictionary size) RAM to create these LZMA archives,
~12GB RAM in my case, but only need ~1*(Dictionary Size) to decompress.

I can provide you 2 files:
PPMD = TestFile_PPMD_1024mb.7z (~1kb)
LZMA = TestFile_LZMA_1024mb.7z (~42mb, contains around 200.000 files

MVV · Post by *MVV » 2013-09-01, 10:07 UTC

BTW Total7zip and 7-Zip file manager fail with both. Context menu shell extension unpacks only PPMD one. Tested with 32-bit 7-Zip and TC.

Do you use 32-bit TC or 64-bit?

Biozynotiker · Post by *Biozynotiker » 2013-09-01, 10:10 UTC

I use 32Bit TC, but these should not be a problem, because 32bit 7zip can handle these archives with any problem.
32bit 7zip can also handle PPMD archives with even higher dictionary like 1500mb.

*EDIT*:
Even TC can't handle such files, there MUST be an error message while testing such archives.

MVV · Post by *MVV » 2013-09-01, 10:40 UTC

Hm, internal TC 7z unpacker really doesn't show error for such files (Total7zip does).

Post by *ghisler(Author) » 2013-09-01, 15:09 UTC

I can confirm that internal 7zip (32-bit) cannot unpack either of these due to lack of memory. I will show an error message. 64-bit TC works fine.

Biozynotiker · Post by *Biozynotiker » 2013-09-01, 15:20 UTC

I don't understand why is there not enough memory, when there is enough ram available?
Extraction of thes archives needs around 1GB ram,
and TC (32bit) should easy allocate around 1,4gb ram (if available).
So why can 7zip (32bit) can handle this?

EDIT:
BTW, Rar5 also can use 1gb dictionary!

MVV · Post by *MVV » 2013-09-01, 15:35 UTC

Biozynotiker,
Which 7-Zip version do you use?

I'm using 9.20 and it can't unpack your files (I wrote about it above).

Biozynotiker · Post by *Biozynotiker » 2013-09-01, 15:47 UTC

@MVV
I use the latest stable (7.20, 32Bit, 7zg.exe) to decompress, and (7.20, 64Bit) to compress.

I use the 32Bit version to decompress, because it works on nearly all systems.
BTW, Total7zip, which, so far as i know, use the official 7z.dll, can handle this without any problems (just installed for testing).

So, on my system, there must enough memory available to allocate more than 1gb ram in 32bit mode.

MVV · Post by *MVV » 2013-09-01, 16:48 UTC

My Total7zip uses 7z.dll from 7-Zip 9.20 installation.

1. I tried to unpack TestFile_LZMA_1024mb.7z via Alt+F9 using Total7zip: it did something but I got empty directory structure.
2. I tried to unpack TestFile_LZMA_1024mb.7z via context menu unpack command using 7-Zip: it did the job using 1 GB of RAM.
3. I tried to unpack just file TestFile_PPMD_1024mb.7z via Alt+F9 using Total7zip: got empty dir.