Hi Stephen, I would like to know the behavior of ext3 for a write() request used with O_SYNC for 64 K in term of disk access method: - is there a chance to have only one disk access (instead of 16 x 4 K corresponding to each mapped page ) or at maximum two in journaled mode ? - if this is possible then how can i force such a grouping of data in a single disk output ? NB: i disable cached write at diskdrive level. regards, Eric