> But even then there can be buffering inside the disk this, the system accounts for. If you tell the OS to sync data to disk, it has to make sure that the dis

> But even then there can be buffering inside the disk this, the system accounts for. If you tell the OS to sync data to disk, it has to make sure that the disk committed the data to the durable media. One aspect of this is: As the disk, as long as it has unwritten cached data in its internal RAM cache, is free to write that data basically in any order, the OS will have to send a write barrier to the disk. Wouldn't this been accounted for by the OS, all filesystems would basically be completely broken on most power outages. Or one would have to flush the disk cache completely on every single and small change, which would severely degrade performance.