8.3 filename

An 8.3 filename (also called a short filename or SFN) is a convention used by old versions of DOS and versions of Microsoft Windows prior to Windows 95 and Windows NT 3.5. It is also used in modern Microsoft operating systems as an alternate filename to the , to provide compatibility with legacy programs. The filename convention is limited by the . Similar 8.3 file naming schemes have also existed on earlier CP/M, TRS-80, Atari, and some Data General and Digital Equipment Corporation minicomputer operating systems. 8.3 filenames are limited to at most eight characters (after any directory specifier), followed optionally by a consisting of a period and at most three further characters. For systems that only support 8.3 filenames, excess characters are ignored. If a file name has no extension, a trailing has no significance (that is, and are equivalent). Furthermore, file and names are uppercase in this system, even though systems that use the 8.3 standard are usually case-insensitive (making equivalent to the name ). However, on non-8.3 operating systems (such as almost any modern operating system) accessing 8.3 file systems (including DOS-formatted floppy disks, but also including some modern memory cards and networked file systems), the underlying system may alter filenames internally to preserve case and avoid truncating letters in the names, for example in the case of VFAT. VFAT, a variant of FAT with an extended directory format, was introduced in Windows 95 and Windows NT 3.5. It allowed mixed-case Unicode s (LFNs) in addition to classic 8.3 names by using multiple for long filenames (in such a way that old 8.3 system software will only recognize one as the valid directory entry). To maintain backward-compatibility with legacy applications (on DOS and Windows 3.1), on FAT and VFAT filesystems, the operating system automatically generates an 8.3 filename for every LFN, through which the file can [also] be opened, renamed, or deleted, although the generated name (e.g. ) may show little similarity to the original.