Using Samba, Second Edition

Name Mangling and Case

Back in the days of DOS and Windows 3.1, every filename was limited to eight uppercase characters, followed by a dot, and three more uppercase characters. This was known as the 8.3 format and was a huge nuisance. Windows 95/98/Me, Windows NT/2000/XP, and Unix have since relaxed this problem by allowing longer, sometimes case-sensitive, filenames. Table 8-4 shows the current naming state of several popular operating systems.

Table 8-4. Operating system filename limitations

Operating system	File-naming rules
DOS 6.22 or below	Eight characters followed by a dot followed by a three-letter extension (8.3 format); case-insensitive
Windows 3.1 for Workgroups	Eight characters followed by a dot followed by a three-letter extension (8.3 format); case-insensitive
Windows 95/98/Me	255 characters; case-insensitive but case-preserving
Windows NT/2000/XP	255 characters; case-insensitive but case-preserving
Unix	255 characters; case-sensitive

Samba still has to remain backward-compatible with network clients that store files in just the 8.3 format, such as Windows for Workgroups. If a user creates a file on a share called antidisestablishmentarianism.txt, a Windows for Workgroups client cannot tell it apart from another file in the same directory called antidisease.txt. Like Windows 95/98/Me and Windows NT/2000/XP, Samba has to employ a special method for translating a long filename to an 8.3 filename in such a way that similar filenames will not cause collisions. ...