Hammer: Transactional file updates

[Joerg Sonnenberger]

On Sun, Aug 17, 2008 at 08:40:20PM +1000, Dmitri Nikulin wrote:
> I personally believe that Unix should have had a transactional file IO
> API from the start, so that all modern file systems would implement it
> and atomicity would be the standard, not a rare feature.

I am not exactly sure what you mean with "atomicity", but can you
demonstrate even *one* filesystem where writes of two processes are
atomic relative to each other? I don't know any.

There are also very good reasons why Unix filesystem IO never was
transactional. It is way too expensive and complex to allow that.

Joerg