Installation of Windows XP into Boot Camp requires the use of a USB optical drive -- it cannot be installed via the Remote Disc function. In addition, some discs, such as DVD movies and game discs, may be copy-protected and therefore unusable through DVD or CD Sharing. The function also cannot be used to playback movies or audio CDs. Finally, pressing the eject key on a Windows system will automatically eject a disc that is being used by Remote Disc. Some third-party headphones may not plug into the MacBook Air headphone jack because part of the connector does not fit within the port hatch. Apple says "In some instances, it may appear to fit, but the audio quality is intermittent or poor when used with MacBook Air." This issue can be solved by using a third-party headphone adapter to extend the audio connection outside of the port hatch. Regarding system migration, Apple recommends use of a wired network (using a USB-to-Ethernet adapter). "This should be much faster that using a wireless connection. For the best experience, be sure to attach your source and target computers to the wired network before you start." You should also avoid letting your source computer go to sleep while you are attempting to migrate. The Apple Hardware Test is included on the MacBook Air's startup drive. You can access it by holding down the "D" key during startup. If that method doesn't work, you can use another computer and Remote Install Mac OS X to run Apple Hardware Test. Make sure to install Remote Install Mac OS X on the other computer. Another document notes that your MacBook Air may shut down when a USB device is plugged in if the device is defective or the USB port has shorted out. This is to protect itself if there is an 'over-current' on the USB bus. The solution is to remove the offending USB device. With regard to usage, a document outlines (with pictures) how to use the trackpad gestures on the MacBook Air. For instance, two-finger pinching lets you zoom in or out on PDFs, images, photos, and more.