Re: reiserfs empirical study (very long)
On Wed, 30 May 2001, Andrew Sharp wrote:
> Geert Uytterhoeven wrote:
> > On Wed, 30 May 2001, Andrew Sharp wrote:
> > > The big endian patches change the code to use little endian ordering
> > > for all on-disk structures. IMO this is a mistake, and certainly
> > > costs a dear performance penalty, because on big endian processors,
> > > this method requires converting endianness both ways (reading and
> > > writing) for all meta data. I submit that there is little reason
> > > for this, and the performance cost is not worth the very dubious
> > > feature of having the file system be moveable to little endian
> > > systems, like x86. Note that except in few cases, the disk labels
> >
> > We had the same discussion many years ago about ext2fs, and a few years later
> > about XFS. In fact m68k and ppc used to have a big-endian ext2fs.
> >
> > Now ext2fs is defined to store metadata in little-endian order, and XFS to
> > store metadata in big-endian order. This was done for interoperability reasons.
> >
> > Since people do want to exchange disks between machines, the alternative was to
> > support both endiannesses. In fact m68k did have a bi-endian ext2fs for a
>
> I would actually like to hear more about these discussions. Are
> there any archives? Are they too old? Geez, if some silly person
M68k switched from big-endian to standard (little-endian) ext2fs in 1995.
PPC followed in late 1996.
Check out mailing list archives for Linux/m68k, Linux/PPC, and probably
linux-kernel as well.
> wants to take a disk from one machine to another, well, that is what
> vfat is for, no? ~:^)
If the system disk of my PPC box dies, I'll be happy to restore it from backup
on some other machine...
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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