Target disk mode

Target Disk Mode is a boot-up option on Macintosh computers. It allows a computer in Target Disk Mode to be mounted as an external hard drive by another computer over FireWire or Thunderbolt.

It is accessed by holding the "T" key on the keyboard during computer startup. Some models allow the host computer to use the external drives connected to the target Mac or even use its optical drive.

Supported interfaces

 * FireWire
 * SCSI (early PowerBook era)
 * Thunderbolt
 * USB 3.0 (or later, built into logic board)