[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

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...



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

Reply to: