What is the "MagSafe" power connector? How does it work? How was it designed to not cause data loss?

Apple's website is fairly vague on details regarding the "MagSafe" power connector. As you may have read already, it simply says that it is:

A magnetic connection instead of a physical one. So, tripping over a power cord won't send MacBook Pro flying off a table or desk; the cord simply breaks cleanly away, without damage to either the cord or the system. As an added nicety, this means less wear on the connectors.

MacWorld expanded on Apple's description a bit, noting that the:

MagSafe connector is made up of a magnetic ring surrounding four small power nubs; when you move it close to the MacBook [Pro], the magnetic attraction takes over and it snaps in place. There's no up or down on this connector--it's perfectly symmetrical, so either direction works fine. A small light (on both top and bottom of the connector) indicates your MacBook [Pro]'s charging status.

It is worth acknowledging that similarly designed power cables previously have been used with a variety of kitchen appliances -- deep fryers, slow cookers, and fondue pots, for example -- as reported by C|Net, referencing an earlier CNN article. However, this is the first time that a magnetic power connector has been used on a notebook computer. A patent also provides additional information on how this similar type of power connector is used in kitchen appliances.

It is interesting that the general rule has been not to put a magnet even near a computer practically forever, and now Apple has magnetic power connectors on the MacBook Pro and MacBook, and magnetic remote holders on the iMac G5 and later models.

In a "myth busting" article, PCWorld reported that even inexpensive store bought magnets do in fact destroy the data held on obsolete floppy disks, but "most modern storage devices, such as SD and CompactFlash memory cards, are immune to magnetic fields" and "the same goes for hard drives. The only magnets powerful enough to scrub data from a drive platter are laboratory degaussers or those used by government agencies to wipe bits off media."

However, regardless of what PCWorld says, page 30 of the MacBook Pro User's Guide warns that:

The MacBook Pro power adapter port contains a magnet that can erase data on a credit card, iPod, or other device. To preserve your data, keep these and other magnetic media away from the power adapter port.

Page 106 further warns to "not place magnetically sensitive material or devices within 1 inch (25 mm)" of the MagSafe power connector. The subsequently published MacBook User's Guide also advises one to be sure that magnetically sensitive items are not stored close to the power connector when the notebook is transported in a suitcase or backpack.

So, the magnets built into recent Apple products should not cause data loss, but one should still be mindful and careful not to place magnetic media -- particularly credit cards and vintage floppy disks or Zip cartridges, but even external hard drives and iPods -- near the magnetic areas of these systems.