Hello, On Tue, 07 Apr 2009, Ashok Gautham wrote: > Data is not written immediately. It is written asynchronously. You > can force it to be written to the disk by using the sync call.. This > call will exit only when all data waiting to be written has been > written (This works even when you have two or more disks where data > remains unwritten)
Not really! See the recent discussion on sync, fsync and so on on LKML or the kernel page of LWN. For example, http://lwn.net/Articles/325420/ says: All [sync] does is preëmpt the normally delayed flushing of dirty blocks by expiring them all. It does *not* write them. They just go on the various disk queues to be written to each device, but that doesn't get them there -- yet. Once upon a time, and on some systems still, there was a user process called update(8) that did this sort of thing every 30 seconds or so. Then there are "write-caching" disk-controllers etc. ... To ensure that data gets written to a removable device you should "umount" it. Then wait for the activity light on the device to go off (if it is not broken!) before unplugging/remove the device. Kapil. -- _______________________________________________ To unsubscribe, email ilugc-requ...@ae.iitm.ac.in with "unsubscribe <password> <address>" in the subject or body of the message. http://www.ae.iitm.ac.in/mailman/listinfo/ilugc
