Most reliable file systems implement journaling mechanisms to handle sudden power failures. As every file modification triggers a commit in the journal, the old state can be recovered in case of any modified metadata. For my understanding, a sudden power loss can only affect the consistency of the data for one single file, which has been interacted with before.
Why then do journaling mechanisms keep track of multiple operations? Wouln't it be enough to just journal the last transaction over and over again? I don't really understand why journaling file systems list multiple transaction records... . With one entry, that gives information about the last file-modification, a consistant state can be recovered, can't it?