220.127.116.11 DOS Filename Restrictions
The older DOS FAT file systems have severe limitations on
file names. These limitations no longer apply to Windows, but they do
apply to DOS based systems such as DJGPP.
A file name may consist of no more than 8 characters, followed by an
optional extension of no more than 3 characters. This is commonly
referred to as an 8.3 file name. Filenames are case insensitive.
There are a couple of filenames which are treated specially. You can
not name a file `aux' or `prn'. In some cases, you can not
even use an extension, such as `aux.c'. These restrictions apply
to DOS and also to at least some versions of Windows.