On Fri, Aug 2, 2013 at 1:32 AM, Rajat Sharma <fs.rajat@xxxxxxxxx> wrote: > On Fri, Aug 2, 2013 at 2:25 AM, neha naik <nehanaik27@xxxxxxxxx> wrote: >> Hi, >> I have some conceptual questions about device driver : >> >> 1. Write order fidelity should be maintained when submitting requests from >> device driver to disk below. >> However, acknowledging these requests it is okay if we don't necessarily >> maintain that order, right? >> > > Yes it should not matter as long as application can rely on data being > written is in order of submission. But it can't ..... unless the write cache is turned off and it is known the the cache is truly off. There is no guarantee of write order in the block stack. Not between the filesystem and the driver. Not between the driver and the drive. There are at least 2 elevators shuffling the order of writes to optimize performance. Rajat, did you get confused? Or were you trying to say something else? Greg _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
