I more or less do not have a problem anymore. Dos 7Z unpacks newer zip files.

Cyberdyne wrote on 2025-12-06, 19:41:

I more or less do not have a problem anymore. Dos 7Z unpacks newer zip files.

I don't understand what exactly the problem was.
What was the utility that failed to unpack the ZIP files from WINZIP 8.8+ ?
Can you upload a small example of problematic ZIP ?

PKZIP failed. But now i know that 7Z opens newer ZIP files. Do not have any examples anymore.

Here's a version of DOS Info-ZIP UnZip that extracted OLDIE.ZIP in DOSBox for me.

I keep it 'cause it seems to go about extracting PKZIP 1.1-packed files (Implode and such) a bit faster than later versions.

MrFlibble wrote on 2025-12-10, 15:07:

Here's a version of DOS Info-ZIP UnZip that extracted OLDIE.ZIP in DOSBox for me.

That's version 5.12 - no support for Deflate64.

I would rather compile my own UnZip 6.00.

its 2025, who in his right mind uses winzip?

Its been Winrar for me since 2000

In Windows yes. Winrar has the best user interface. We are talking about packing algorithms and DOS unpacking. And ZIP file is industry standard. In reality only Deflate is industry standard in my opinion.

Living wrote on 2025-12-10, 22:07:

its 2025, who in his right mind uses winzip?

Its been Winrar for me since 2000

Cyberdyne wrote on 2025-12-07, 10:32:

PKZIP failed.

Cyberdyne wrote on 2025-12-04, 21:29:

2.04g

I think I know what the problem was...

- Some modern ZIP utilities default to Deflate64
- PKUNZIP 2.04g doesn't support Deflate64

and there's several solutions for DOS:

- PKUNZIP 2.50 supports Deflate64
- Info-ZIP UnZip 5.50+ supports Deflate64, doesn't support Reducing from PKZIP 0.9x by default, but it can be compiled in
- aparrently the DOS port of 7Z, but AFAIK it requires 32-bit CPU and a lot of memory

6.3/7/8 had a better icon scheme at least. winzip blue metal compressing orange cabinet > bunch of stupid books

Grzyb wrote on 2025-12-10, 17:44:

That's version 5.12 - no support for Deflate64.

I would rather compile my own UnZip 6.00.

Somewhat recent-ish I played around with compiling different recent versions of UnZip with DJGPP. It worked but somehow it was slower in DOSBox than the precompiled versions. I also suspect that more recent releases are generally less well optimized for slower hardware. I wonder if something could be tweaked in the makefile to improve performance? I'd not looked into it then.

Also UnZip 6.00 uses this annoying time zone variable and prints a message when it can't find one.

But it's good to know that support for legacy compression formats can be turned on in the makefile options.

MrFlibble wrote on 2025-12-11, 10:18:

Also UnZip 6.00 uses this annoying time zone variable and prints a message when it can't find one.

OK - I forgot about this, as I always have TZ set on my DOS machines.
With RTC battery dead or removed, first thing I do after power-on is setting the clock via NTP, which requires proper TZ variable.