This is a good explanation I'd forgotten about. You were probably the one
who explained it to me a little time ago... Long time...

Karl

<quote who="Glenn Herbert">
>    Because of the manner in which the write subsystem was implemented, it
>    is  NOT  a  trivial task to either pre-detect or recover from a system
>    write  failure,  which  is  usually the cause of the corruption.   The
>    group  structure  (which  will be comprised of one or more buffers) is
>    modified  in  memory,  and then shipped off to the system for writing;
>    there  is no way to determine if in fact any particular write actually
>    made  it  TO  disk.   If a write() operation returned successful, then
>    that is the only validation we can check;  if the system burps on that
>    buffer  later down the chain, there is no way to detect that.   Having
>    spent  better  than  10  years  in  the file system, there was serious
>    discussion  of  how  to  do  this,  but  unfortunately required a very
>    serious  rewrite  of  the  write subsystem; obviously, that work would
>    never be done.  The various recovery tools shipped with the product do
>    a pretty decent job of recovering as much of the file as possible.
>
>    Hope this helps.
>
>    ______________________________________________________________________
>
>    From: [EMAIL PROTECTED]
>    [mailto:[EMAIL PROTECTED]  On  Behalf Of "Stevenson,
>    Charles" <[EMAIL PROTECTED]>
>    Sent: Wednesday, September 28, 2005 8:10 AM
>    To: <[email protected]>
>    Subject: FW: [U2] Blink Error - Backward Link error
>
>    Do I detect an enhancement suggestion?
>    Whether  this  is  trivial or hard is beyond me, but I tend to believe
>    Mr.
>    Phillips.
>    (On this subject, anyway. I don't know his opinion of the British
>    Royals, for example.)
>    cds
>    -----Original Message-----
>    From: [EMAIL PROTECTED]
>    [mailto:[EMAIL PROTECTED]   On   Behalf   Of  Martin
>    Phillips
>    Sent: Wednesday, September 28, 2005 1:11 AM
>    To: [email protected]
>    Subject: Re: [U2] Blink Error - Backward Link error
>    Why, oh why, doesn't UV fail the write before it corrupts the file? It
>    is trivial to know that this is about to happen.
>    Martin Phillips
>    Ladybridge Systems
>    17b Coldstream Lane, Hardingstone, Northampton NN4 6DB
>    +44-(0)1604-709200
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-- 
karl

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