> offered by case-insenstive filesystem.

Funnily, the current Windows file system (NTFS) is a case-sensitve file system. Case-insensitivity happens on the OS level, more precisely, on the Win32 subsystem level. When you run Windows NT with the POSIX sub system, NTFS is used in its case-sensitive mode. I think, the OS/2 subsystem is case-insensitve, as well. On Windows XP and later POSIX is disabled by default. The last version of Windows NT that shipped with the OS/2 subsystem was Windows 2000, if I'm not mistaken.