13dd8344_ing_guidelines__best_practice___Rationale
[Good practice] File names should not exceed 31 characters. Total length of file paths should be limited to a maximum of 255 characters. Characters are restricted to letters, numbers and _ (underscore) only. [Rationale] 
More than 31 characters can cause problems for some operating systems. Less is better.Although Windows NTFS partitions support filenames up to 256 characters long, the Mac file system can only support up to 31 characters.
DAM » Blog Archive » File naming guidelines (best practice)
Rationale