Long filename is the name given to the longer and therefore more descriptive titles on the FAT filesystem, which was previously restricted to eight characters and a three-character extension (referred to as 8.3 file naming). This improvement first appeared Windows NT 3.5, and was devised by Microsoft. File Allocation Table (FAT) is a partially patented[1] file system developed by Microsoft for MS-DOS and is the primary file system for consumer versions of Microsoft Windows up to and including Windows Me. ... 8. ... Windows NT 3. ... Microsoft Corporation (NASDAQ: MSFT, HKSE: 4338) is an international computer technology corporation with 2005 global annual sales of US$39. ...

The long filename system can support up to 255-character names, including spaces and non-alphanumeric characters (excluding the following characters, which have special meaning within the command interpreter: / : * ? " < > |). COMMAND.COM is the name for the default operating system shell (or command line interpreter) for DOS and 16/32bits versions of Windows (95/98/98 SE/Me). ...

To maintain compatibility with older operating systems, Microsoft formulated a method of generating an 8.3 filename from the long filename (for example, "Microsoft.txt" to "MICROS~1.TXT") and associating it with the file.

Compatibility issues

The way Microsoft added support for LFNs to the FAT filesystem was by adding bogus directory entries to the filesystem to store the longer names. The reason they choose to do this is compatibility; older programs could still access the files while newer ones could see the longer names. File Allocation Table (FAT) is a partially patented[1] file system developed by Microsoft for MS-DOS and is the primary file system for consumer versions of Microsoft Windows up to and including Windows Me. ...

When LFNs were first introduced into a MS-DOS based operating system with Windows 95 the implementation caused some problems when people used older programs. Any program that changed the FAT directly could lose all of your long filenames. Also if booting into plain DOS the long filenames would not be visible. At the same time Microsoft decided not to update many of the older programs to support LFNs. Of those, one that particularly stands out is the program WinFile the Windows for Workgroups 3.11 File Manager. Under Windows NT 3.51 and Windows NT 4.0 WinFile supports LFNs, however the Windows 95 version of the WinFile program came from Windows for Workgroup 3.11. OS/2 had its own method of supporting LFNs incompatible with Microsoft's, however this can be rectified with a driver. Microsofts disk operating system, MS-DOS, was Microsofts implementation of DOS, which was the first popular operating system for the IBM PC, and until recently, was widely used on the PC compatible platform. ... A boxed copy of Windows 95 Upgrade. ... The Windows 3. ... It has been suggested that this article or section be merged with . ... Windows NT 4. ... OS/2 is an operating system created by Microsoft and IBM, later developed by IBM exclusively. ...

LFN drivers

The following is a list of drivers that can be used to provide support for long file names used in Windows 95:

Similar implementations

Prior to the release of Windows NT; one of the first file systems to support long name and spaces was the Macintosh file system for the original version of MacOS on the Macintosh 128K. It was an innovation ahead of it's time. Then, the Hierarchial file system was introduced for mac systems a few years after. Windows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. ... Mac OS, which stands for Macintosh Operating System, is Apple Computer’s name for the operating systems for Macintosh computers. ... For in-depth technical information, see Macintosh 128K technical details. ...

OS/2 is an operating system created by Microsoft and IBM, later developed by IBM exclusively. ... DR-DOS is a DOS-family-compatible operating system for IBM PC-compatible personal computers, originally developed by Gary Kildalls Digital Research and derived from CP/M-86. ... It has been suggested that FreeDOS-32 be merged into this article or section. ...

External links

• The filesystems howto
• Current version of DOSLFN
• Original Author of DOSLFN
• [1] VFAT OS2 Provides LFN support under OS2]
• Microsoft documentation for filenames in Windows XP