The 19 digit EML filename is an Epoch timestamp

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Brian Boone

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Oct 24, 2013, 12:16:24 AM10/24/13
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First... Gmvault is an excellent program. I am using it on Windows 7 x64. It's fast and solid.

So, I was curious about the 19 digit filename of EML files.
   e.g.  1448236294136020484.EML

Each EML file has a companion .META file.
In that file will be the same filename number labeled as gm_id
   e.g.  "gm_id": 1448236294136020484

No luck googling "gm_id"

So I compared several EML filename numbers each a year apart.

I found that the 19 digit numbers are Epoch timestamps at a very high resolution.
The resolution is  2**20 * 1000 = 1,048,576,000  counts/sec

Given one of the 19 digit numbers divide by  1,048,576,000 and then do the normal Epoch conversion.
   e.g.   1448236294136020484   an e-mail from Mon, 07 Oct 2013 04:35:57 -0700 (PDT)

            1448236294136020484 / 1,048,576,000 = 1,381,145,757 ignoring the fractional part

Using Perl to convert ... perl -e "print scalar(localtime(1381145757))"
                                      Mon Oct  7 07:35:57 2013
that's for Eastern Daylight Saving

An older e-mail ...     1323683120380853806 an e-mail from Fri, 01 Jan 2010 08:16:35 -0800 (PST)
convert in one step   perl -e "print scalar(localtime(1323683120380853806 / 1048576000))"
                                 Fri Jan  1 11:16:34 2010

By the way I found a very good website about Epoch conversions.
It has a calculator to do one conversion and examples of how to do
conversions in many different languages.

http://www.epochconverter.com/site/sitemap.php

Brian

  



Guillaume Aubert

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Oct 24, 2013, 5:41:13 AM10/24/13
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Hi Brian,

Many thanks for your support and thanks for this useful information. 

Just one question what is your point ?

Should we use this information for something else ?

The gm_id is the email id used by Google to store the emails in the Gmail datastore. This is the unique identifier for an email.

Thanks for letting me know about your potential good idea behind that informational email.

Cheers,
Guillaume 




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Brian Boone

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Nov 2, 2013, 8:42:47 PM11/2/13
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Hi Guillaume,

I thought I had replied yesterday but I don't see it here. Posting again.

Curiosity was the main reason I looked into the format of the 19 digits
in the .EML file names. When Google searches did not find anything
for  gm_id  I was very motivated to do my own deciphering.

I am thinking about one use: rename all my EML files to a format like
   yyyy-mm-dd-AM-hh-mm-ss-ddd.eml
              PM

I find such a format very useful, having used it before.

I would have to consider a collision strategy if I did not use a
ddd part long enough to support the maximum resolution of the
gm_id  epoch format.

The  gm_id  epoch file names would make such a renaming project
very easy and yet precise for every file.

Regards,
Brian
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