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Talk:Make a backup file: Difference between revisions
→Why no copying?: Less work
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Backup involves copying, and must do since otherwise it is the same file and will be modified by the subsequent update. (Or alternatively it has to have some very special support from the OS; there's no POSIX operation for “checkpoint this file to this other name without copying” IIRC.) The whole strength of backups comes from copying. –[[User:Dkf|Donal Fellows]] 15:42, 11 November 2011 (UTC)
: This depends on the OS and on the pattern of accesses applications use on the file. Under unix, if anything has the file open for writing, then renaming it means they will update the backup. But if everything uses the "rename and write new copy" system, then it can be safe (though, of course, there's also the issue of more recent backups overwriting older backups). --[[User:Rdm|Rdm]] 15:48, 11 November 2011 (UTC)
: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)
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