PSN-L Email List Message

Subject: Re: PSN file format and long file names.
From: Bob Smith bobsmith5@........
Date: Tue, 10 Jul 2001 06:51:14 -0400

A brief comment on relative (binary vs. ASCII) file formats from a non
seismologist, non-PSNer.

I suspect that *once compressed* by a good file compression program such
as PKZIP or WINZIP, the size difference will be much less that you might
think at first.  Consider:

1.  Expanding a binary file to ASCII format does not, indeed *cannot*,
add information to the file (unless, of course, the conversion program
modifies the information content of the binary file in the process but,
then you are not comparing apples to apples anymore.)

2.  The goal of a good *lossless* compression program program (PKZIP /
WINZIP) is to eliminate redundancies and  minimize entropy.  The
information content of the compressed file is identical to the original
file (thus loss less).

As a practical exercise, I suggest that someone, I don't have access to
sample files, convert a few binary format files to ASCII, compress them
both and compare both the pre compressed and post compressed files and
their size ratios.

	Sincerely, Bob Smith

Larry Cochrane wrote:
> Mauro,
> Not to beat a dead horse I will only make a few more comments about ASCII
> verses Binary. I do want to get some feedback from other members on long
> file name standard for the PSN event files.
> Mauro Mariotti wrote:
> > On the expandibilty of PSN4 format (touchè) i'm not examined it well
> > even if the expandibilty of a binary record is not too easy to manage
> > especially
> > for people that wants to stick one standard but is not so much expert on
> > programming tecniques.
> First, its not that much more difficult to deal with binary files.... Also,
> I don't think a standard should be created or designed around the ability of
> someone's programming skills. This is not to say it should be so
> complicated, like the SEED format, that even a skilled programmer has
> problems extracting data from it.
> >
> > Using archive compressor the 8 char filename length is a problem.
> > Your winquake when access a database of events do a great work analizying
> > and reporting
> > date time location and comments on the file you're opening.
> > If the events file are compressed you cant'do that with winquake.
> > Using long names you could create a database readable with Computer
> Resource
> > of windows
> > creating filenames like:
> >
> > 20000701_145023_PG_E-W_KURILI-ISLANDS_M6.5.TXT
> >
> > I think you should modify SDR to use long names.
> > If i'm not in wrong SDR is DOS based and this can't be done.
> > Anyway this is my viewpoint:
> Since SDR is a DOS program it is limited to the 8.3 format. WinQuake and my
> archival system could save the files using a longer name. I would like to
> start a discussion on the new file name format. You can see Mauro proposal
> above. I propose a shorter format:
> Example: 20010705.234505.bhz.lc1.psn
> This is similar to how other seismic data archive systems on the net store
> event files.
> The first two set of numbers are the date and time followed by the component
> type like BHZ or LHN and then the sensor ID, this can be 2 to 6 characters
> long. By ending the file in PSN, Windows can associate it as an event file
> and open it with a program like WinQuake if someone clicks on the file name
> using Explorer. Maybe just 2 characters for the year would be ok? This will
> become a problem in about 90 years! Anyone else want to suggest a format?
> -Larry Cochrane
> Redwood City, PSN
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Robert L. (Bob) Smith			Smith Machine Works, Inc.
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Larry Cochrane <cochrane@..............>