FireWire

How it tests

Offered when the quick pass finds the FireWire controller driven (firewire_ohci) and the Mac's own node on the bus. Watches the FireWire bus, twice a second, for a node other than the Mac's own: a drive, a camera, another Mac in Target Disk Mode. It names the device from the configuration ROM the Mac read over the cable. With a port map, each FireWire 400 and 800 port is ringed and asked for in turn. Nothing is mounted, read or written: a FireWire disk is made read-only the moment it appears, and the sleep tests wait until it's unplugged, since a Mac can hang going to sleep with one attached.

How it decides

Supported: a new node showed up after the screen opened (a device already plugged in has to be unplugged and plugged back in); with a port map, on every port. Partial: on some ports only. Failed: on a Mac with FireWire, the quick pass found no controller, no driver or no bus, or a device was plugged in and nothing showed up (“Nothing shows up”, after 15 s).

How sure it is

A new node proves the port, the cable's link and the bus, and that the Mac read the device's ROM across it. No more than that crosses the cable: it reads nothing from a drive.

What could mislead it

• Could pass when it shouldn'tA drive shows up as a node even if it couldn't move data: the test reads nothing from it.
• Could fail when it shouldn'tNothing shows up from a device without power, or from a FireWire 400 device on an 800 port through the wrong cable or adapter.