Using file names in vDos-lfn in a long file name environment

[Wengier]

(Note: This thread is about general knowledge regarding Windows-style long file names vs. DOS 8.3 or short names related to the vDos-lfn branch; for download of vDos-lfn, including both the Windows binary and source code, please see the thread at: https://sourceforge.net/p/vdos/discussion/modifiedvdos/thread/c1ef5b3f/ )

vDos is a DOS emulator for Windows, which may map to actual Windows drives in its emulated DOS environment with its "USE" command. However, while Windows allows file names up to 255 characters, traditional DOS file names only allow up to 11 characters, with the first 8 characters as its main file name, and the last 3 characters as its extension. This is known as the short or 8.3 file names, in contrast to the Windows long file names, or LFN. For example, "C:\Program Files" is a directory commonly seen in Windows, and it has a corresponding DOS 8.3 name, i.e. "C:\PROGRA~1". If there is also another Windows path named for example "C:\ProgramData", it probably has a corresponding DOS 8.3 name named "C:\PROGRA~2". In both real DOS environments or under DOS emulators such as DOSBox, "C:\PROGRA~1" and "C:\PROGRA~2" (or even "C:\Program Files" and "C:\ProgramData" if LFN is enabled) will be seen using directory listing commands such as DIR. While unmodified versions of vDos deliberately hide such files or directories, the vDos-lfn branch will display them. The DIR command in vDos-lfn will also display Windows-style long file names to the right of the DOS 8.3 names, similar to a Windows 9x DOS prompt or a real MS-DOS 7 environment with DOSLFN installed. With this users will be able to find long file names (as displayed in Windows) corresponding to their respective DOS 8.3 names easily.

Apart from its 4DOS 8.0 shell, which supports Windows-style long file names, there are also many LFN-aware applications under DOS such as MS-DOS 7 EDIT, which will be able to see and operate with both the long file names and their corresponding DOS 8.3 names. PKZIP/PKUNZIP 2.50, QuickView Pro 2.60, MPXPLAY and Doszip Commander are some other such examples (you can see even more examples at http://www.cn-dos.net/msdos71/doslfns.htm). Since vDos-lfn provides supports for long file name functions similar to that of DOSLFN, these programs will be able to see and operate with Windows-style long file names (in addition to DOS 8.3 names) in vDos-lfn directly. However, older DOS programs generally don't support Windows-style long file names. Microsoft Word for DOS, Microsoft QBASIC and PKZIP/PKUNZIP 2.04 are such examples, which will only be able to see and operate with DOS 8.3 names. In such cases users must provide the coresponding DOS 8.3 names to them as their inputs. If a newer version of such a program is available which supports long file names (e.g. PKZIP/PKUNZIP 2.50 instead of 2.04), it is recommended to use the newer version instead in order to support both Windows-style long filenames and DOS 8.3 names. DJGPP programs generally support long file names under DOS.

For more information and download links relating to my LFN-supporting versions of vDos and DOSBox, you can visit the page made by emendelson here:

http://wpdos.org/dosbox-vdos-lfn.html