> Why will timemachine greatly reduce it? Mac's TimeMachine uses a filesystem technique called Copy-on-Write (COW). http://en.wikipedia.org/wiki/Copy-on-write
Say you created a file 5 days ago and haven't touched it since. That means all the daily and hourly backup snapshots of that file have not changed for 5 days. In fact, using COW, all those snapshot copies are pointers to the original file (or the first backup copy in the second disk). If you change the file, the most recent pointer will become a real copy of the file before the write is made to the original. This way you can make lots of backup snapshots without consuming too much disk space. This is a neat idea and it has been around for many years. I've used a couple of network filesystems that used this idea to make backup snapshots which were then dumped to tape as nightly backups. Some SANs use this method to make multiple snapshots of the same data and offer Read-Only copies. What Apple has done is to make it easier to use it on a desktop OS. Plus, certain apps (iPhoto, Mail, etc) can recover files from within the application. Sun's new ZFS also offers the same multiple snapshots with COW, but without a cool GUI. ************************************************************************ * ==> QUICK LIST-COMMAND REFERENCE - Put the following commands in <== * ==> the body of an email & send 'em to: [EMAIL PROTECTED] <== * Join the list: SUBSCRIBE COMPUTERGUYS-L Your Name * Too much mail? Try Daily Digests command: SET COMPUTERGUYS-L DIGEST * Tired of the List? Unsubscribe command: SIGNOFF COMPUTERGUYS-L * New address? From OLD address send: CHANGE COMPUTERGUYS-L YourNewAddress * Need more help? Send mail to: [EMAIL PROTECTED] ************************************************************************ * List archive from 1/1/2000 is on the MARC http://marc.info/?l=computerguys-l * List archive at www.mail-archive.com/[email protected]/ * RSS at www.mail-archive.com/[email protected]/maillist.xml * Messages bearing the header "X-No-Archive: yes" will not be archived ************************************************************************
