On Jan 22, 2008, at 8:56 PM, Linus Torvalds wrote:

quoted text
> On Tue, 22 Jan 2008, Theodore Tso wrote:
>>
>> It's pretty clear the Unicode conversion is being done in HFS+, not  
>> in
>> the VFS layer of Mac OS X.
>
> Ok. That's going to make it both easier and harder for them in the  
> future.
> In particular, it probably means that their VFS layer really has no  
> notion
> of this at all, and it's going to be fairly hard to support any kind  
> of
> generic "backwards compatibility" layer on top of other filesystems.

HFS+ was developed on Mac OS 8, which I believe didn't have the notion  
of a VFS, or at least not one that would have been in any way capable  
of doing the case-insensitivity and normalization necessary. However,  
I'm not sure what you mean by a "backwards compatibility" layer on  
other filesystems - if you mean treating another filesystem like HFS+,  
well, if you're using a filesystem that doesn't do normalization then  
the VFS really shouldn't do it for you.

quoted text
>> So presumably if and when Mac OS adopts ZFS, they will be able to be
>> free of this mess, at least if they care about being compatible with
>> Solaris.
>
> I wouldn't hold my breadth on ZFS, considering the memory  
> requirements.
> ZFS apparently wants *lots* of memory:
>
> 	http://www.solarisinternals.com/wiki/index.php/ZFS_Best_Practices_Guide#ZFS_Administra...
> 	http://wiki.freebsd.org/ZFSTuningGuide
>
> in fact it seems that the FreeBSD people basically recomment against  
> using
> ZFS on 32-bit kernels because of the memory use issues.
>
> Yes, it could be BSD-specific, but considering Solaris has the same
> recommendation, it sure seems like ZFS isn't ready for prime time on  
> any
> low-end (read: consumer) hardware.
>
> Of course, in a year or two, 2GB will be the norm. Right now it's  
> still
> fairly unusual on Mac hardware outside of the Mac Pro line (which, I
> think, comes with a *minimum* of 2GB), and the people who get it  
> want it
> not for the filesystem caches, but for big photo editing jobs..

Actually, interestingly the new MacBook Air comes with 2GB stock (I'm  
assuming it's soldered onto the motherboard, though, so it makes sense  
that Apple's giving customers 2GB as they can't upgrade themselves).

In any case, everybody's making a big fuss about ZFS, but it really  
doesn't make a lot of sense to use for a consumer system, it seems  
more geared for a server.

-Kevin Ballard

-- 
Kevin Ballard
http://kevin.sb.org
kevin@sb.org
http://www.tildesoft.com