Seven months after the first iMacs shipped with Thunderbolt, there are only a couple of Thunderbolt-capable peripherals available. Why? At Macworld, Joel Mathis looks into that question, suggesting that the problem revolves around Thunderbolt’s complexity and cost. follow link
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Hold down F9, F10, F11, or F12 (or whatever you've set for the Expose and Spaces keyboard shortcuts) for a few seconds, and then release the key to enter and leave the appropriate mode without having to press the key again. This is particularly useful for Dashboard, in which you can check the contents of a widget and then return to your work with only a single key press.
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Where Are the Thunderbolt Devices?