Long filenames are cut off when viewed in MS-DOS due to not supported.
Cause:
MS-DOS version shipped with Win95 automatically creates an 11-character alias for every long filename, to convert it to standard DOS file-naming convention. File names are sorted on this basis. Or, the long filename has been destroyed when the file was saved in Windows 3.x or backed up with a utility that does not support long filenames.
Solution:
There is no workaround. If the file was saved in Windows 3.x, the rest of the filename has been lost.