When Apple introduced the MacBook Air in 2008, it was the first Mac in many years not to include an internal optical drive, even as an option. You can buy an external SuperDrive to go with it, but what happens if you don't have one and you need to start your Mac from a CD or DVD? Apple's answer is clever: You put the disc in another computer (Mac or PC) and share it over the local (wired or wireless) network.
Although you can use conventional file sharing (described later in this chapter) to share an optical disc over a network, DVD or CD sharing is different in that it treats the shared disc exactly as though it were directly connected to your Mac. That means, among other things, that you can boot from it, which isn't true of optical discs shared as regular network volumes.
Mac OS X 10.5.2 and later versions include the software needed to share an optical disc; Windows users can download comparable software from Apple. But whereas any Mac with an optical drive can activate DVD or CD sharing to make that drive available to others, at present, only a Mac without a built-in optical drive can see and use the shared drive.
To make your optical drive available to other Macs on the local network without an optical drive, follow these steps:
Choose System Preferences ...