Windows XP allows file names upto 255 characters in length while the upcoming Windows Vista allows even longer filenames containing upto 260 characters.
While filenames are generally never so long, there are still two very important precautions that must be considered while you are giving descriptive names to your Windows files.
Point A: The limit of 255 characters for Windows XP or 260 character limit for Windows Vista applies to the entire filepath and not just the filename.
For instance, if the directory name is D:\abc - the maximum length of the filename that this folder can hold is just 249 characters since the other six characters are grabbed by the full directory path. The rest 249 characters should include the dot or period [.] and the filename extension as well.
Point B: This is relevant to podcasters who produce content in MOV, MP4 or MP3 formats that will be played inside the Apple Quicktime player.
The Windows version of Quicktime player cannot play podcasts with filenames longer than 63 characters and that length limit includes the mandatory period and the file name extension.
If you try to play a file in Quicktime with a lengthy name, it will refuse to play and return an "Error-37: a bad filename or volume name was encountered" [see screenshot] There are currently no workarounds to bypass this limit on Quicktime.
I found this Quicktime limitation just by chance while trying to watch Scoble's shoot with Flock co-founder Geoffrey Arone on The Scoble Show.
The video interview is available in Quicktime MOV format but since the filename was more that 63 characters, I could not play it on my Windows machine. It did not even show up in the iTunes list. So renamed the file to a smaller name [<63 characters] and it worked just fine. [Quicktime Version 7.1.3]