Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: Notesfiles $Revision: 1.6.2.14 $; site uiucdcs.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxl!cbosgd!ihnp4!inuxc!pur-ee!uiucdcs!acheng From: acheng@uiucdcs.UUCP Newsgroups: net.unix-wizards Subject: Hanoi Algorithm - (nf) Message-ID: <13700058@uiucdcs.UUCP> Date: Sat, 18-Aug-84 11:25:00 EDT Article-I.D.: uiucdcs.13700058 Posted: Sat Aug 18 11:25:00 1984 Date-Received: Mon, 20-Aug-84 00:36:38 EDT Lines: 40 Nf-ID: #N:uiucdcs:13700058:000:1521 Nf-From: uiucdcs!acheng Aug 18 10:25:00 1984 #N:uiucdcs:13700058:000:1521 uiucdcs!acheng Aug 18 10:25:00 1984 I am setting up some dump schedules for our machine and want to try this famous "Hanoi algorithm" mentioned in the "man dump". ---------------------------------------------------------------- Now a short suggestion on how to perform dumps. Start with a full level 0 dump dump 0un Next, dumps of active file systems are taken on a daily basis, using a modified Tower of Hanoi algorithm, with this sequence of dump levels: 3 2 5 4 7 6 9 8 9 9 ... For the daily dumps, a set of 10 tapes per dumped file sys- tem is used on a cyclical basis. Each week, a level 1 dump is taken, and the daily Hanoi sequence repeats with 3. For weekly dumps, a set of 5 tapes per dumped file system is used, also on a cyclical basis. Each month, a level 0 dump is taken on a set of fresh tapes that is saved forever. ---------------------------------------------------------------- After studied it for a while, I could not follow the logic. 1) If there is always a level 1 weekly dump, at most 6 daily tapes are needed. How come "a set of 10 daily dump tapes"? 2) For a level n dump, it dumps all files modified since the latest level m dump (m < n; NOT <= n). So, there is no difference between the following 2 sequences, is there? 3 2 5 4 7 6 9 8 9 9 ... 3 3 5 5 7 7 9 9 9 9 ... Can any earthlings explain this Hanoi algorithm to me? Albert Cheng ihnp4!uiucdcs!acheng acheng%uiuc@csnet.arpa