[hfs-user] HFS+ Inconsistent Creation Dates

Rob Leslie rob@mars.org
Fri, 7 May 2004 11:58:10 -0700


On May 7, 2004, at 4:43 AM, Pierre Duhem wrote:
> Norton v. 8, when checking some of my volumes, complains about dates.
> For instance :
> The files have creation dates that are inconsistent or outside the
> expected range.
>
> Dates are computed that way:
> - use of unix (C lib) time/filetime functions to get the number of
> seconds from January the 1st, 1970,
> - add the number of seconds from January 1st, 1904
> - add the timezone + summertime (-7200 seconds currently for
> Paris/Madrid) to get the UTC/GMT time.
>
> Following the HFS+ spec, I don't add the timezone + summertime for the
> volume dates.
>
> That way, I have correct dates. PC files copied to a Macintosh volume
> appear with a correct date on a Mac, and so on.
>
> I don't understand what Norton's error message could mean.
>
> Any clue?

Keep in mind that UNIX dates (seconds since Jan. 1, 1970) are signed 
while HFS dates (seconds since Jan. 1, 1904) are unsigned.

      UNIX        HFS           Date (UTC)
   ==========  ==========  ====================
   0x80000000  ----------  Dec 13 20:45:52 1901
   0x83da4f80  0x00000000  Jan  1 00:00:00 1904
   0x00000000  0x7c25b080  Jan  1 00:00:00 1970
   0x7fffffff  0xfc25b07f  Jan 19 03:14:07 2038
   ----------  0xffffffff  Feb  6 06:28:15 2040

HTH.

-- 
Rob Leslie
rob@mars.org