Re: Howto implement device detection without thrashing

[Rob Browning <rlb@cs.utexas.edu>]

Wichert Akkerman <wichert@cs.leidenuniv.nl> writes:

> This is slightly different in that you don't sync a file, but tell
> the system to do all operations synchronously, ie sync on every
> operation. But for this it indeed works.

I could be wrong, but my impression from listening to the SCSI,
transaction processing, and log-structured file system people was that
even if you tell the OS to sync, there's no clear way to tell for sure
that the data has been *physically* written to disk.  A sudden power
interruption could still cause trouble.  It's been a while since I was
reading the relevant arguments, but I think I recall that this is
because disks (and fancy disk controllers) have their own on-board
cache with no clear standard way to tell them to actually dump to the
physical media.

FWIW

-- 
Rob Browning <rlb@cs.utexas.edu> PGP=E80E0D04F521A094 532B97F5D64E3930