Use the new MacBook SD cardslot as a boot device and more.

Apple's replacement of the ExpressCard slot with a SD card reader may seem like a limitation to some people, but given the popularity of SD cards for cameras and video recorders, as well as for other electronics devices the move makes marketing sense, and the slots may just be more useful than they appear at first glance.

There have been many questions about the specifics of the SD card's usage, and Apple has compiled them into a FAQ that they've posted in this knowledgebase article, with troubleshooting advice, ways to manage formats and partitions, and alternate uses for the card besides data storage.

Essentially, SD cards will behave just like an external hard disk drive, and as such and given their ever-increasing capacities, can be used as an alternative way to boot a system, just like using a FireWire or USB external drive. Just format the card to Mac OS Extended and give it a GUID partition map in Disk Utility, and you can install a copy of OS X to it for troubleshooting your main installation (or even as your primary boot device if you so choose).

The card reader should be fully functional in all operating systems that support it, so BootCamp users should still recognize inserted media. At 240Mbit/sec the data transfer rate of the card reader is about half that of USB2 and FireWire connections, but still should be enough to run and use for alternative booting.

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