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    SubjectRe: RFC: from FIBMAP to FIONDEV
    On Thu, Jun 17, 1999 at 11:34:30AM +0100, Stephen C. Tweedie wrote:
    > Hi,
    > On Tue, 15 Jun 1999 15:58:58 +0200, Matthew Wilcox
    > <> said:
    > > RAID 2,3,4,5 return the data block on the first call and set the
    > > COPIES flag. Subsequent calls set the XOR flag to indicate that the
    > > other blocks should be XORed together to recover the original block.
    > > lilo is perfectly free to ignore this information, but maybe someday
    > > we'll have a good way to use this information.
    > Perhaps this is just unnecessary complexity. After all,
    > > With RAID 1, lilo can install multiple copies of LILO, one on each disc,
    > > each one told about the blocks which exist on its own disc.
    > ... this looks like exactly the right way to do things. Very nice.
    > Short of booting the kernel off the network it looks like the most
    > robust way of doing things right. It is not hard to reserve a small
    > raid-1 partition for /boot even if the rest of your system is
    > raid-<something-bigger-than-one>.

    Okay, I give in. If we do wish to support RAID-1, we still need a way
    of mapping one logical block to multiple physical blocks. I suggested an
    index to the call, Werner suggests a variable length return. Anyone have
    any strong opinions?

    Note that Werner's objection to whether or not the file pointer is
    advanced if one is supposed to make a repeated call can be solved by
    changing FIONDEV to never advance the file pointer, after all the
    application can do this for itself quite easily.

    Matthew Wilcox <>
    "Windows and MacOS are products, contrived by engineers in the service of
    specific companies. Unix, by contrast, is not so much a product as it is a
    painstakingly compiled oral history of the hacker subculture." - N Stephenson

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