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List:       opensolaris-ufs-discuss
Subject:    Re: [ufs-discuss] Re:  Big and little endian
From:       "Gary Thorpe" <gthorpe () myrealbox ! com>
Date:       2007-04-23 15:31:25
Message-ID: 1177342285.c7baa9dcgthorpe () myrealbox ! com
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Darren Dunham wrote:
> > On Sun, 15 Apr 2007, Martin Rosenau wrote:
> 
> [...]
> 
> > No objection to the idea, just we have to keep in
> > mind:
> > 
> > - we don't want to sacrifice native UFS performance
> > - we don't want to make changes to UFS that make it
> > incompatible to old
> > existing filesystems
> 
> 
> Would the result have to be a modified UFS driver?  Especially given the problems \
> mentioned of the conditionals, how about separating it out?  It wouldn't be as \
> useful, but could there be a 'ufsx86' for SPARC and a 'ufssparc' for x86?   
> Both could assume the correct byte-swap instead of a conditional.  Uglier than a \
> unified driver, but the functionality would be appreciated if a unifed one will \
> never be written. 

Just as a point of reference, NetBSD has had support for different endianess in FFS \
for a while (never tested actually sharing disks or familiar with how it works) and \
it doesn't seem to cause a large performance overhead (at least for the native \
endianess case).

See 'options FFS_EI':
http://netbsd.gw.com/cgi-bin/man-cgi?options++NetBSD-current

Since the code is probably radically different I am not sure how helpful it will be, \
but it is out there.




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