Time machine is designed for home users with Mac desktops and notebook computers, and itis fully automated. However, there may be some users or some occasions when itis better not to use Time Machine at all, according to Tom Yager at Infoworld. In addition, Time Machine provides data archiving, but not data protection.

While numerous articles have been written about how Time Machine works, Mr. Yager pointed out some of its limitations and when to ponder whether to use it. "Consider the case of a home user who time-shifts television shows via iTunes, BitTorrent or another source. A sensible user deletes episodes heis already watched to conserve disk space, but when Time Machine is active, it may take a month for that deleted episode to vanish from the backup drive. If the backup drive fills before it can archive 30 daysi worth of data, Time Machine flags an error and quits," Mr. Yager noted. "Deft management of Time Machineis exclusion list is essential for busy systems."

Regarding data backup and protection, Mr. Yager suggested RAID devices: "Time Machine is archiving, not data protection. If your external drive fails, you lose all of your backed up data. Data protection that covers the failure of a storage device calls for a disk array with RAID mirroring or parity striping. If you want to archive and protect your data, which isnit a bad idea if youire a professional Mac user, use a RAID volume as a Time Machine backup device."

One item that Mr. Yager did not point out is that Time machine will, by default, attempt to archive all internal mounted drives. If second internal drive is used for scratch and backup, it should be added to the Time Machine exclusion list.

Mr. Yager approached the use of Time Machine from a professional data backup and protection approach. For users who want to go beyond just backing up their MacBook, he provided some good food for thought.