Re: ZSAV format support [ZCOMPRESSED subcommand]

[soumalya ray]

---

From: Ben Pfaff <address@hidden>
To: Hugo Alejandro <address@hidden>
Cc: "address@hidden" <address@hidden>
Sent: Thursday, 3 October 2013 10:10 AM
Subject: Re: ZSAV format support [ZCOMPRESSED subcommand]

On Wed, Oct 02, 2013 at 01:03:27PM -0400, Hugo Alejandro wrote:
> A few days ago I was recruited to work in the analysis of large surveys,
> what caught my attention is the use of the format *. zsav above *.sav.
>
> Apparently this file format supports higher compression ratio and is more
> efficient with large databases to reduce their size on disk and be faster to
> compress-decompress to create a ZIP file (or other format) with a *.sav file

From here, I think that the next step would have to be to look at both
the .sav and .zsav versions of files.  I would be most interested in
larger files (say, 1 MB in size), because I think that it is likely that
some of the mysteries above would be cleared up if there were more
compressed blocks in the file (or perhaps we would find out that there
is only ever a single compressed block).

Thanks,

Ben.

hi,

after getting the original mail, i searched a little about .zsav. in the user's manual from IBM (ftp://public.dhe.ibm.com/software/analytics/spss/documentation/statistics/21.0/en/client/Manuals/IBM_SPSS_Statistics_Core_System_Users_Guide.pdf), there is a paragraph about zsav in page no 42 (see the attached screenshot). apparently only utf-8 could be used in this manner; and larger the file,higher the time saving using this format!

interestingly, there is a program already available which could read this format- savReaderWriter. i did not try it myself, but according to the main page (http://pythonhosted.org/savReaderWriter/#savwriter-write-spss-system-files), zsav was created using the ZLIB compression scheme. 

searching for more materials.

regards,

 

Dr Soumalya Ray <address@hidden>
MBBS,MD(PGT-C.Medicine),Ex-HP(Medicine)
skype:som3776|twitter:@docbkp

zsav.png
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