On Mon, 19 Sep 2016 13:31:01 -0500, Kevin Minerley wrote:
>Unfortunately, this is working as designed. If indeed it's the sk4t-4949-xx
>deliverable, it is large. As a matter of fact, were it to be be put on a
>dual-layer DVD it wouldn't fit (at least in this pass). Most modern zip
>utilities work against it. Personally, I use 7-zip but when manufactured it's
>the same zip utilities we have been using since the days of physical media.
>
"Unfortunately", indeed. This strikes me as a stonewall.
"modern zip utilities" no. Don't rely on your "Personal..." favorite. Look
at the standard.
As I said at greater length before:
https://en.wikipedia.org/wiki/Zip_(file_format)#Document_Container_File_-_Part_1
ISO/IEC 21320-1:2015 requires the following main restrictions of the ZIP file
format:
Files in ZIP archives may only be stored uncompressed, or using the
"deflate" compression
(i.e. compression method may contain the value "0" - stored or "8" -
deflated).
(Sorry for the wikipedia indirection, but the entire ISO/IEC 21320-1:2015
requires $$.)
I have kept c2784301.zip and k4t49497.zip. Neither of those uses any format
other
than "stored" or "deflated". Something has changed "since the days of physical
media".
Perhaps someone chose different options to 7-zip as Charles conjectured.
Perhaps
the supplier changed the defaults. 7-zip tells me that k4t4949b.zip uses at
least
methods LZMA:24 and BCJLZMA:24, contrary to ISO/IEC 21320-1:2015. Something
has changed.
Here, I'll call on Postel's Law (I often disagree with it, but here it's
appropriate):
Validate it with the "jar" utility that IBM distributes.
I extracted k4t4949b".zip" with 7-zip and rearchived it with Info-zip.
The result:
1118616064 Sep 19 11:34 k4t4949b.zip
1228358648 Sep 19 13:12 SK.zip (re-zipped with Info-zip)
so: rxx "say 1118616064 / 1228358648 "
0.910659168
Incompatibility and standards deviation are too high a price to pay for
a (roughly) 9% saving in space.
I extracted the re-zipped archive with z/OS 2.2 jar (it took a l-o-o-o-ng
time, but it's a test). And the re-zipped and re-extracted files compared
exactly with those extracted by 7-zip.
Finally, as a couple others have said, change the filename extension to
".7z" since it's not a .zip file. This can be done overnight; it's not
necessary to wait three months or so for the next full refresh.
-- gil
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