With the change to IDE drives starting with the PowerBook 150 and 190, Apple implemented HD Target Mode, which essentially enabled SCSI Disk Mode by translating the external SCSI commands via the ATA driver.
A unique system control panel on the PowerBook was used to select a non-conflicting SCSI ID number from the host Mac. Originally called SCSI Disk Mode, a special cable allowed the original PowerBook series to attach to a desktop Mac as an external SCSI disk.
As long as the requisite software appeared in the system ROM, the Mac could be booted into disk mode. Target Disk Mode is the preferred form of old-computer to new-computer interconnect used by Apple's Migration Assistant.Īpple introduced disk mode access with the PowerBook 100 and continued to offer it with most of the subsequent PowerBook series and Firewire equipped Macs. All of the volumes on all of the computers will be available to the host computer at the end of the chain. It is possible to daisy chain several Macs together by booting them each to Target Disk Mode. When booted to TDM, all of the computer's attached volumes ( HFS+ volumes, MS-DOS volumes, DVD-ROM, etc.) appear as devices attached to the hub. "Target Disk Mode." "Developer Connection". Target Disk Mode (sometimes referred to as TDM or "Target Mode") is a boot mode for Macintosh computers wherein the Mac does not load the operating system, but instead behaves as a FireWire mass storage device with the SBP-2 (Serial Bus Protocol) standard.