Whether to upgrade the ZIP normative reference from appnote 6.2.0 vs. 6.3.2 (6.3.3)

[Arms, Caroline]

If we are considering citing 6.3.3,  I think we need to bring the possibility of citing ISO 21320-1 back on the table.  The argument made against that at Seattle, according to the minutes, was that the effort of comparing 6.2 with 6.3.3 (which is what ISO 21320-1 refers to) was not worthwhile.

Like Murata-san, I believe that 6.3.3 and 6.3.2 are equivalent as specifications with the, admittedly many, changes all representing improved formatting for the document, including paragraph numbering to support more specific citation.  Changes between 6.2.0 and 6.3.2 should be easier to check with a diff.  I’m not certain how Murata-san made his comparison.

My own analysis of changes associated with chronological versions of APPNOTE (done for a different purpose) is in the History section of Notes near the bottom of http://www.digitalpreservation.gov/formats/fdd/fdd000354.shtml
6.3.2 is not on the list.  When I did this analysis, I reckoned that changes between 6.3.0 and 6.3.3 were “minor changes, such as corrections or support for an additional compression method.”  I am fairly certain I based my analysis on reading change logs.

My personal preference would be to refer to ISO 21320-1  rather than APPNOTE 6.3.3 unless there is a technical reason not to do so.

    Caroline


Caroline Arms
Library of Congress Contractor
Co-compiler of Sustainability of Digital Formats resource    http://www.digitalpreservation.gov/formats/

** Views expressed are personal and not necessarily those of the institution **

From: eb2mmrt at gmail.com [mailto:eb2mmrt at gmail.com] On Behalf Of MURATA Makoto
Sent: Tuesday, March 31, 2015 10:01 PM
To: SC34
Subject: Whether to upgrade the ZIP normative reference from appnote 6.2.0 vs. 6.3.2 (6.3.3)

Dear colleagues,

I quickly compared 6.2, 6.3, and 6.3.3.   Technically, I find
three issues: (1) more hash algorithms, (2) UTF-8, and
(3) OPC Growth Hint.  I prefer 6.3.3 to 6.2, because of (2).
How do you feel?

Regards,
Makoto


>    6.3.0         -Added tape positioning storage          09/29/2006
>                   parameters

Irrelevant since OPC does not use tape positioning storage parameters.

>                  -Expanded list of supported hash algorithms

Three values of Hash ID are added.

             0x8007          RIPEMD160
             0x800C          SHA256
             0x800D          SHA384
             0x800E          SHA512

>
>                  -Expanded list of supported compression
>                   algorithms

Irrelevant since OPC uses DEFLATE and nothing else.


>                  -Expanded list of supported encryption
>                   algorithms

Irrelevant since OPC does not use ZIP encryption.
>
>                  -Added option for Unicode filename
>                   storage

This is important if we would like to allow verbatim UTF-8.

>                  -Clarifications for consistent use
>                   of Data Descriptor records
>
>                  -Added additional "Extra Field"
>                   definitions

This addition includes Growth Hint of OPC.  If the
OPC revision uses 6.3.3, it would look more consistent.
But OPC already has Growth Hint anyway.

>    6.3.1         -Corrected standard hash values for      04/11/2007
>                   SHA-256/384/512
>
>    6.3.2         -Added compression method 97             09/28/2007
>
>                  -Documented InfoZIP "Extra Field"
>                   values for UTF-8 file name and
>                   file comment storage

We should prohibit this field.

>
>    6.3.3         -Formatting changes to support           09/01/2012
>                   easier referencing of this APPNOTE
>                   from other documents and standards

This is not technical but purely editorial.  But if you compare 6.3.3
and preceding versions, you will find very many differences.

--

Praying for the victims of the Japan Tohoku earthquake

Makoto
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