At 07:13 AM 11/29/2004, Janet L Nelson wrote:
>I am hoping that some of our members who are more technology savvy than me
>can shed some light on a problem we ran into this week-end.
<snip of long file/path name problem>

>Does any one have any experience with this? Any suggestions on how to
>handle this?
>
>Thanks.
>
>Janet
>***********************************

Unfortunately, file path length has long been a problem. Different versions
of the Windows OS support different maximum lengths of file names and total
file paths, and individual programs all too often run into a problem with
this as well, on their own. Ideally, the OS would be the limiting factor
(so that if a user can create a path, it would work everywhere), but this
is often not the case.

Before Windows 95 / NT 3.51, you were limited under the MS-DOS FAT file
system to the 8.3 format for file names ("pronounced eight-point-three by
most propeller heads", an MS technote states) - eight characters before the
extension, and three after. Most Windows system files still follow this
naming scheme for maximum compatibility, and many older programs are still
limited by it. Windows has some capacity to translate file names on the fly
for DOS based programs, by dropping anything over eight characters before
the first period/decimal point encountered (while doing a bit of numbering
with the last few characters if needed), and truncating anything after the
last three characters past the period/decimal point. Thus, when you look at
"My Happy Long File Name.document" in a DOS window, it may appear as "My
Hap~1.doc". The max path size was 80.

See http://www.chami.com/tips/windows/122496W.html

This was followed by VFAT, which allows 255 characters per name, and NTFS,
which allows 256. The total path length for VFAT is 260, so if you have a
255 long character name, and include a required terminating null character,
that only leaves you 4 characters for the path. I don't think NTFS actually
has a max path lenght as part of it's specification, but in practical
terms, most programs do.

Non-floppy disks benefited from HPFS, which allowed more types of
characters (such as spaces) in it's 254 max length file name.

Note that a path at the root level is 3 characters minimum - "C:\" is as
short as you get. Folder names can add up pretty quickly as you start
nesting them.

Fun, huh? And this isn't even considering cross platform (Macintosh, UNIX)
issues.

Anyway, the executive summary rule of thumb is - your path + file name
should be limited to 259 characters, and no more than 254 should be the
file name.

The next limiting factor will be the maximum path ability of any program
that must handle the files. In this case, it looks like whatever backup
software your IS folks are using - ask 'em what the limit is. Perhaps they
can suggest (or create) a utility for checking path lengths, so that long
names can be fixed by your folks before IS has to fix 'em.

In general, try and not go overboard on the file name length - while it's
handy to have lots of info in the file name, this must be weighed against
the problems in compatibility this might cause. Probably the biggest cause
of problems is deep nesting of folders - that is, folders (possibly with
long names) within folders within folders, etc. Try to keep folder names
short, or don't do deep nesting.

Anyway, that's what I can think of on the subject.  Hope it's helpful.


Michael Edwards
Blank & Associates P.S.  -  206.256.9699 x36
2001 Western Avenue, Suite 250  -  Seattle, Washington 98121

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