On Wed, 16 Jan 2008, Kevin Ballard wrote: > > I believe it exists because HFS+ was created at a time when the Mac was moving > from a multi-encoding world (which was a nightmare) to a Unicode world and > they wanted to remove ambiguity in filenames. But I wasn't around when they > made this decision so this is just a guess. I do agree. And I think starting out case-insensitive (something they must really hate by now) also made it less of an issue. When you're case-insensitive, the issues with any UTF-8 normalization are simply swamped by all the issues of case, so you probably don't even think about it very much. The big problem with any name rewriting is that I can open file 'xyz', and I literally have a very hard time knowing whether that file I know I opened and created has anything to do with the file 'Xyz' that I see when I do a readdir(). Are they the same? Maybe. But it's literally hard to tell on OS X. I can do an fstat() on my file descriptor and on the directory entry, and if they get the same d_ino they *probably are the same entry, but even then it actually could have been a hardlink (and my 'xyz' is really *another* name for it entirely, and the filesystem is actually case-sensitive and 'Xyz' was a *different* name that somebody else did!). See? If you're creating a content tracker, these kinds of issues are not "idle chatter". It's really *really* important. Was that file the one I was told to track? Or was it a temporary file that was just hardlinked? This is why case-insensitivity is so hard: you have a very real "aliasing" on the filesystem level, where all those really *different* pathnames end up being the same thing. And all the same issues show up with utf-8 rewriting, so if you normalize utf-8 names, you actually end up having almost all the same problems that a case-insensitive filesystem has. They're just much rarer in practice, so you just won't hit them as often - but when you do, they are equally painful! (In fact, they can be a whole lot *more* painful, because now they are really rare, and really confusing when they happen!) But if you come from a case-insensitive background, all the UTF-8 rewriting really looks like such a small problem compared to all the horrid problems that you had with different locales and cases, so I suspect they didn't even realize what a big mistake they did! Linus - To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
