Talk:Make a backup file: Difference between revisions

:It seems faster to just rename the file. With copying it goes like this: create the new file (.backup), copy the contents of the old file to the new file, clear the old file, write new data to the old file. Without it goes like this: rename the old file to a new name (.backup), create the old file again (already empty), write new data to the newly created file (with the old name). --[[User:Mwn3d|Mwn3d]] 15:52, 11 November 2011 (UTC)

:good question. thanks for asking. copying is more expensive than rename. copying can fail (due to lack of space for example). if the machine dies before the copied file is written to the disk, which may be some time after the OS signaled that the copy is complete, and you already started to write the to the old file, then both may be lost. rename guarantees that the data is not touched, and thus can hardly be corrupted. and i don't think a rename could cause a file to be deleted if the machine crashes while a rename happens. it's either got the old name or the new one (or in very obscure situations maybe both). as far as i can tell, <code>rename()</code> is posix. at least the <code>rename(2)</code> manpage makes that claim. it is atomic too...--[[User:EMBee|eMBee]] 16:06, 11 November 2011 (UTC)