Subject: Re: Unicode support in kernel
To: None <>
From: Noriyuki Soda <>
List: tech-kern
Date: 10/15/1999 14:47:28
>   Why do you need Unicode support in the kernel?  The tables are a  
> lot of crap to stow in the kernel.

Yes. I'd like to avoid it, but...

At least, Long filename extenstion to MS-DOS FAT filesystem requires
Unicode support in kernel, since it encodes filename as both UCS-2 and
codepage-dependent-codeset. Thus, for example, if userland specified
a filename as Shift_JIS, kernel has to translate it to Unicode, and
the reverse is also true.
I suppose Joliet extention to CD9660 filesystem has same problem.

NTFS doesn't have this problem, though.

>   The Mac OS X filesystem API's are all still char*.  What we do is  
> we treat char* strings as UTF8.  Read Unicode from disk as UTF8 and  
> present that to userland.  Higher-level toolbox calls deal with the  
> translation buisiness in user space.

Traditionally, encoding of UFS is not defined, and is locale dependent,
how does Mac OS X solve this problem?
How does Mac OS X support Shift_JIS encoded legacy hfs?