The file naming convention used by the legacy MS-DOS and Microsoft Windows 3. x operating systems. 8.3 filenames use the following naming convention for file and directory names:
The reason for the file naming limitation on these platforms has to do with the way the FAT file system was designed. The file allocation table (FAT) allocates only enough space for an eight-character name followed by a three-character extension. The extension identifies the type of program that can open or run the file. For example, the file resume.doc would be identified to the operating system as a file that can be opened using Microsoft Word, since the .doc extension is registered by the operating system as the extension for Word documents.
More recent versions of Windows such as Windows 95, Windows 98, Windows NT, and Windows 2000 use long filenames (LFNs), which are more descriptive than the shorter ones.