Case-Insensitivity Support

Traditionally, UNIX and POSIX file systems have case-sensitive file names. SAM-QFS file systems already support the case-sensitive behavior. The SMB service requires case-insensitive behavior. In order to support the SMB service in SAM-QFS, a mixed-mode behavior has been implemented. The mixed-mode behavior indicates that the file system can support requests for both case-sensitive and case-insensitive matching behavior.

When a case-insensitive matching request is made of a mixed-sensitivity file system, the behavior is generally the same as would be expected of a purely case-insensitive file system. The difference is that a mixed-sensitivity file system might contain files or directories with multiple names that are unique from a case-sensitive perspective but not unique from the case-insensitive perspective.

For example, a directory might contain files foo, Foo, and FOO. If a request is made to case-insensitively match any of the possible forms of foo (for example foo, FOO, FoO, fOo, and so on), one of the three existing files is chosen as the match by the matching algorithm. The file that the algorithm chooses as a match is not guaranteed, but the same file will be chosen as a match for any of the forms of foo. The file chosen as a case-insensitive match for foo, FOO, foO, Foo, and so on, is always the same as long as the directory remains unchanged.