[IGS-DCWG-70] Re: [IGS-DCWG-68] Re: [IGS-DCWG-67] Re: [IGS-DCWG-65] Change in compression scheme

Thu Apr 1 08:48:39 PDT 2010

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IGS-DCWG Mail      01 Apr 12:42:21 PDT 2010      Message Number 70
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Author: Carey Noll

   bzip2 will provide better compression according to my system
administrator. He is currently running some tests of various
compression utilities; I will send a summary report to the DCWG
when he has finished his tests.

   I would recommend doing these changes in steps. Let's tackle
this proposed compression change first before we start thinking
about more "drastic" changes such as in filenaming, etc. That is
my preference/recommendation anyways!

   I also would like to encourage more feedback on Mike Schmidt's
earlier email proposal for OCs to push data to all global data
centers. It sounds to me like an "easy" implementation to help
keep data current and available at all GDCs.

Thanks,
Carey.
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On Apr 1, 2010, at 11:42 AM, Nacho Romero wrote:

> ******************************************************************************
> IGS-DCWG Mail      01 Apr 08:42:59 PDT 2010      Message Number 68
> ******************************************************************************
>
> Author: Nacho Romero
>
> You are absolutely correct bzip2 is indeed everywhere, not sure why i
> got in my head to look for bzip!!  crazy!
>
> still I prefer .gz ... now for even less of a reason!  :)
>
> indeed if .Z/.gz/.bz2 show clear winner on .10d files I will also
> move to change all our scripts but we need to clearly justify and
> explain the improvement and/or benefits before initiating IGS-wide
> discussions. Parallel existence of files should also be proposed, for
> how long?
>
> Is this a good time to rethink the filenames of GNSS data files?? ...
> to make the data's origin more unambiguous, we discussed this in the
> IC at the start (Agenda point 2 in
> http://www.canarygnsscenter.org/IC/IC_MoM_20091208.pdf) and the DCWG
> should speak on this issue now, what do you think? this even affects
> the RINEX format documentation (Chapter 4), they are apparently just
> recommendations to use the historical 8.3 naming, do we have to raise
> this issue now? ...
>
> regards,
> Nacho
>
> At 08:22 -0700 1/4/10, Stowers, David A (3350) wrote:
>> ******************************************************************************
>> IGS-DCWG Mail      01 Apr 08:22:28 PDT 2010      Message Number 67
>> ******************************************************************************
>>
>> Author: Dave Stowers
>>
>> I have no major stake in this, but I think you'll find "bzip2" and "bunzip2"
>> in all of the O/S types mentioned below, including MacOSX.
>>
>> Redhat-based distributions (at least) often compress contents within
>> standard .rpm packages using bzip2.
>>
>> Sun Linux also provides updates in .tar.bz2 form.
>>
>> Sun Solaris has been issuing patches for bzip2 for several years.
>>
>> SunOS ... really?
>>
>> Winzip, version 11 or later supports all of the mentioned compression
>> types (.Z, .gz, .bz2).
>>
>> In other words, the issues appear to be hardcoded or scripted software
>> dependencies, and whether there really are space (and therefore cost)
>> savings at large data centers.
>>
>> I have not performed .Z/.gz/.bz2 testing in years, and do not expect to
>> do so now. I just need advance warning and an implementation plan,
>> should it be so decided.
>>
>> -dave
>>
>>
>> On Apr 1, 2010, at 12:51 AM, Nacho Romero wrote:
>>
>>>
>>> ******************************************************************************
>>> IGS-DCWG Mail      01 Apr 07:59:07 PDT 2010      Message Number 65
>>>
>>> ******************************************************************************
>>>
>>> Author: Nacho Romero
>>>
>>> Dear all,
>>>
>>> As Mike has mentioned already the issue of WIIIDE support is
>>> essential, for most users the .Z is already an issue as 99% of people
>>> grow up knowing only .zip so switching to .bz2 files is going to seem
>>> "foreign" to most users (non-expert).  I am assuming that Winzip can
>>> handle .Z, .zip, .bz2 and .gz files transparently these days but I do
>>> not use Windows anymore so no idea, please someone confirm, thanks.
>>>
>>> If there is not that much difference I would suggest .gz, which is
>>> already an improvement over .Z, since "gzip" is more common and well
>>> known. On Hatanaka compressed files the difference "should" not be
>>> too large with .bz2 but I have not checked this in a long time so I
>>> am open to be contradicted.
>>> Also bzip does not seem to be in the baseline distributions of Linux
>>> Ubuntu, or OS X, or SunOS, the operating systems that I generally
>>> use, whereas gzip is always available by default.  This is just my
>>> opinion and bias showing so take it for what it is worth but I think
>>> .gz is better known than .bz2
>>>
>>> On the Hatanaka side I expect continued support from GSI and as the
>>> source code is available I have never had any problem compiling it in
>>> different platforms.  Mike; this is something that we need to also
>>> chase from the RINEX side in the IC! we will initiate contacts with
>>> GSI to see what their position is on RINEX3.0, just to be sure.
>>>
>>>
>>> regards,
>>>
>>> Nacho
>
>
> best regards,
>
> Nacho
>
> _______________________________________________________________
>
> Ignacio (Nacho) Romero
> Aerospace Engineer, PhD
> SAC s.l. at Navigation Support Office (ESA/ESOC)
> nng.esoc.esa.de
> www.canaryadvancedsolutions.com
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-----
Ms. Carey Noll
Manager, Crustal Dynamics Data Information System (CDDIS)
Secretary, ILRS Central Bureau
NASA GSFC
Code 690.1
Greenbelt, MD 20771
USA

E-mail:  Carey.Noll at nasa.gov
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