8.3

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8.3 (also 8-point-3-names mentioned) is a notation commonly used for the restrictions which file names in FAT - file systems , such as CP / M , DOS and versions of Windows prior to Windows 95 are subjected. Similar restrictions also exist for certain Data General and DEC file systems .

8.3 file and directory names consist of a maximum of eight letters or numbers, followed by a period (“.”) And the name extension , which can consist of a maximum of three characters. In file and directory names, no distinction is made between upper and lower case; as a rule, upper case letters are used (i.e. lower case letters are not permitted). Furthermore, some special characters are not allowed, as these are control characters (e.g. colon, question mark, asterisk) or are assigned differently in different code pages , e.g. the path delimiter in Germany (code page 850) is the backslash ("\") and in Japan (Code page 932) the yen symbol ("¥"), although their internal file system encoding is identical.

With Windows 95 and Windows NT 3.5 , VFAT was introduced as a variant of the FAT file system with extended directory entries. This made longer file names written in upper and lower case (“Long File Name”) possible in the MS-DOS and Windows “world” in addition to the 8.3 scheme.

In order to maintain downward compatibility with older applications, an 8.3 variant is also entered in the directory for each long file name, under which older programs can handle such files.

Proceed as follows under Windows:

  1. If the file name only consists of capital letters or digits in the 8.3 scheme, no LFN variant is created.
    Example: TEXTFILE.TXT
  2. If the file name corresponds to the 8.3 scheme but contains uppercase and lowercase letters, this is saved as a LFN, while an uppercase 8.3 variant is also created.
    Example: TextFile.Txt is also TEXTFILE.TXTregistered as.
  3. Other file names are saved as LFN and an 8.3 variant is also registered. This consists of the first 6 characters of the file name in capital letters, extended by a tilde ("~") and a consecutive number, followed by a point and the first three capitalized characters of the name extension.
    Example a): TextFile1.Mine.txt becomes TEXTFI~1.TXT(or TEXTFI~2.TXT, if TEXTFI~1.TXTalready exists).
    Example b): becomes (or , if already exists).WordFile1.docxWORDFI~1.DOCWORDFI~2.DOCWORDFI~1.DOC
  4. If the preceding methods do not lead to a unique 8.3 file name, the long file name (LFN) is shortened to two characters, followed by a random 4-digit hexadecimal number , which in turn is followed by a tilde and a number, followed by the name extension.
    Example: TextFile.Mine.txt could TE021F~1.TXTbecome.

The 8.3 names are usually regenerated in each directory. If files are copied or moved, depending on the sequence in which they are processed, the numbering of the short file names may change if there are several similar file names. Example: First one is Meine Datei.txtcreated which is given the short name MEINED~1.TXT. Then one is Meine Daten.txtcreated which MEINED~2.TXTreceives. If the second file is the first to be copied or moved to a new directory, Meine Daten.txtthe short name is given MEINED~1.TXTand the second file copied is given the short Meine Datei.txtname MEINED~2.TXT.

Problems can arise if files have lost their long file names (for example, processing with old programs, transfer via incompatible systems) and an LFN file with this name already exists as a short name. You will then be asked whether the file should be overwritten. This can also happen if both files previously existed peacefully in a common directory. Example: There is one MEINED~1.TXT. In addition, there is a file Meine Datei.txtwhich is given the short name MEINED~2.TXTbecause "~ 1" has already been taken. If it is now Meine Datei.txtmoved first in the processing sequence (because processing is carried out according to file date, for example) it is given the name MEINED~1.TXT. In the case of the one that is moved afterwards MEINED~1.TXT, which only has this file name and no long file name, it is then determined that the file name has already been assigned.

The NTFS file system of the Windows NT variants is based on the LFN system, but also supports the 8.3 scheme. The latter support can be deactivated in order to increase the processing speed.

The ISO 9660 file system used by CDs allows file names with up to 31 characters, but many burning programs also support the 8.3 naming scheme here for reasons of compatibility.

Individual evidence

  1. ↑ support.microsoft.com: Disable 8.3 filename creation on NTFS partitions