* w32 file-attributes on FAT32 volume vs.same on NTFS volume - bugp? @ 2009-05-20 19:46 MON KEY 2009-05-20 20:02 ` Eli Zaretskii 0 siblings, 1 reply; 5+ messages in thread From: MON KEY @ 2009-05-20 19:46 UTC (permalink / raw) To: emacs-devel (file-attributes "u:/a/w32path/on/FAT32/formatted/removable/drive") ;;;=>(t 1 0 0 (18948 65472) (18950 1330) (18950 1328) 0 "drwxrwxrwx" t (7484788 . 1152) (25026 . 58322)) ;;; why is `nth 4' (e.g. Last access time) of that list giving the weird time-value on FAT32 drive? (current-time-string (quote (18948 65472))) ;;;=>"Sat May 09 00:00:00 2009" Whereas on a similarly directory created on an NTFS volume I get: (file-attributes "c:/Documents and Settings/path/on/a/w32path/NTFS/formatted/drive") ;;;=>(t 1 1004 513 (18964 23862) (18957 32124) (18944 28179) 0 "drwxrwxrwx" nil 0 (45128 . 62390)) (current-time-string (quote (18964 23862))) ;;;=>"Wed May 20 15:42:46 2009" Am I missing something? s_P ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: w32 file-attributes on FAT32 volume vs.same on NTFS volume - bugp? 2009-05-20 19:46 w32 file-attributes on FAT32 volume vs.same on NTFS volume - bugp? MON KEY @ 2009-05-20 20:02 ` Eli Zaretskii 2009-05-21 2:15 ` MON KEY 0 siblings, 1 reply; 5+ messages in thread From: Eli Zaretskii @ 2009-05-20 20:02 UTC (permalink / raw) To: MON KEY; +Cc: emacs-devel > Date: Wed, 20 May 2009 15:46:19 -0400 > From: MON KEY <monkey@sandpframing.com> > > (file-attributes "u:/a/w32path/on/FAT32/formatted/removable/drive") > ;;;=>(t 1 0 0 (18948 65472) (18950 1330) (18950 1328) 0 "drwxrwxrwx" t > (7484788 . 1152) (25026 . 58322)) > > ;;; why is `nth 4' (e.g. Last access time) of that list giving the > weird time-value on FAT32 drive? > (current-time-string (quote (18948 65472))) > ;;;=>"Sat May 09 00:00:00 2009" > > Whereas on a similarly directory created on an NTFS volume I get: > (file-attributes "c:/Documents and > Settings/path/on/a/w32path/NTFS/formatted/drive") > ;;;=>(t 1 1004 513 (18964 23862) (18957 32124) (18944 28179) 0 > "drwxrwxrwx" nil 0 (45128 . 62390)) > > (current-time-string (quote (18964 23862))) > ;;;=>"Wed May 20 15:42:46 2009" > > Am I missing something? I think you are missing the fact that on FAT32, the last-access time actually records only the date, with no time. Whereas on NTFS, it's a full-fledged time stamp. ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: w32 file-attributes on FAT32 volume vs.same on NTFS volume - bugp? 2009-05-20 20:02 ` Eli Zaretskii @ 2009-05-21 2:15 ` MON KEY 2009-05-21 3:28 ` Eli Zaretskii 0 siblings, 1 reply; 5+ messages in thread From: MON KEY @ 2009-05-21 2:15 UTC (permalink / raw) To: Eli Zaretskii; +Cc: emacs-devel > I think you are missing the fact that on FAT32, the last-access time > actually records only the date, with no time. That would be the culprit :) per wikipedia: (URL `http://en.wikipedia.org/wiki/File_Allocation_Table#Directory_table'); :Byte Offset 0x10 :Length 2 :Description Create date. The year, month and day are encoded according to the following bitmap :Bits 15-9 :Description Year (0 = 1980, 127 = 2107) :Bits 8-5 :Description Month (1 = January, 12 = December) :Bits 4-0 :Description Day (1 - 31) :Byte Offset 0x10 :Length 2 :Description Last access date; see offset 0x10 for description. While it is prob. unreasonable to assume Emacs document the vagaries of myriad filesystems (esp. non-free ones), when examining the docstring - e.g. `file-attributes' - it is not at all possible to deduce that _some_ file-systems will return correct but counter-intuitive results: ``4. Last access time, as a list of two integers. First integer has high-order 16 bits of time, second has low 16 bits. 5. Last modification time, likewise. 6. Last status change time, likewise.'' Are there other filesytems with similar un-features? If so, is it an actively used one - i.e. not antiquated, obsolete, deprecated, non-free, etc.? s_P On Wed, May 20, 2009 at 4:02 PM, Eli Zaretskii <eliz@gnu.org> wrote: >> Date: Wed, 20 May 2009 15:46:19 -0400 >> From: MON KEY <monkey@sandpframing.com> >> >> (file-attributes "u:/a/w32path/on/FAT32/formatted/removable/drive") >> ;;;=>(t 1 0 0 (18948 65472) (18950 1330) (18950 1328) 0 "drwxrwxrwx" t >> (7484788 . 1152) (25026 . 58322)) >> >> ;;; why is `nth 4' (e.g. Last access time) of that list giving the >> weird time-value on FAT32 drive? >> (current-time-string (quote (18948 65472))) >> ;;;=>"Sat May 09 00:00:00 2009" >> >> Whereas on a similarly directory created on an NTFS volume I get: >> (file-attributes "c:/Documents and >> Settings/path/on/a/w32path/NTFS/formatted/drive") >> ;;;=>(t 1 1004 513 (18964 23862) (18957 32124) (18944 28179) 0 >> "drwxrwxrwx" nil 0 (45128 . 62390)) >> >> (current-time-string (quote (18964 23862))) >> ;;;=>"Wed May 20 15:42:46 2009" >> >> Am I missing something? > > I think you are missing the fact that on FAT32, the last-access time > actually records only the date, with no time. Whereas on NTFS, it's a > full-fledged time stamp. > ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: w32 file-attributes on FAT32 volume vs.same on NTFS volume - bugp? 2009-05-21 2:15 ` MON KEY @ 2009-05-21 3:28 ` Eli Zaretskii 2009-05-23 9:11 ` Eli Zaretskii 0 siblings, 1 reply; 5+ messages in thread From: Eli Zaretskii @ 2009-05-21 3:28 UTC (permalink / raw) To: MON KEY; +Cc: emacs-devel > Date: Wed, 20 May 2009 22:15:16 -0400 > From: MON KEY <monkey@sandpframing.com> > Cc: emacs-devel@gnu.org > > While it is prob. unreasonable to assume Emacs document the vagaries > of myriad filesystems (esp. non-free ones), > when examining the docstring - e.g. `file-attributes' - it is not at > all possible to deduce that _some_ file-systems will return correct > but counter-intuitive results: I will add some comment to the doc string. > Are there other filesytems with similar un-features? Only some other FAT-based ones (VFAT, for example), AFAIK. ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: w32 file-attributes on FAT32 volume vs.same on NTFS volume - bugp? 2009-05-21 3:28 ` Eli Zaretskii @ 2009-05-23 9:11 ` Eli Zaretskii 0 siblings, 0 replies; 5+ messages in thread From: Eli Zaretskii @ 2009-05-23 9:11 UTC (permalink / raw) To: monkey, emacs-devel > Date: Thu, 21 May 2009 06:28:17 +0300 > From: Eli Zaretskii <eliz@gnu.org> > Cc: emacs-devel@gnu.org > > > Date: Wed, 20 May 2009 22:15:16 -0400 > > From: MON KEY <monkey@sandpframing.com> > > Cc: emacs-devel@gnu.org > > > > While it is prob. unreasonable to assume Emacs document the vagaries > > of myriad filesystems (esp. non-free ones), > > when examining the docstring - e.g. `file-attributes' - it is not at > > all possible to deduce that _some_ file-systems will return correct > > but counter-intuitive results: > > I will add some comment to the doc string. Done. ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2009-05-23 9:11 UTC | newest] Thread overview: 5+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2009-05-20 19:46 w32 file-attributes on FAT32 volume vs.same on NTFS volume - bugp? MON KEY 2009-05-20 20:02 ` Eli Zaretskii 2009-05-21 2:15 ` MON KEY 2009-05-21 3:28 ` Eli Zaretskii 2009-05-23 9:11 ` Eli Zaretskii
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