Target Disk Mode

Work in Progress

Target disk mode is a fancy firmware feature provided by Apple since 1999. It essentially allows you to boot a Mac as if it were an external hard drive, and read the hard drive on another machine via firewire. Turns out, the host computer (the one reading the target drive) doesn't have to be running OSX, it just has to be able to read the file system on the drive. For our purposes, we won't be reading data, just over-writing the drives with a new operating system. Linux can read HFS+ just fine*, no problem, anyhow. So there.

*A caveat is that Linux will not be able to create, write to, or mount HFS+ filesystems without the hfsprogs, hfsutils and hfsplus packages (in Debian-based distros). Depending on whether you're booting a live environment, a console-based installer, or a standard installed environment, these packages may not be available.
Scellef 02:00, 15 August 2012 (UTC)

http://www.1394ta.org/press/WhitePapers/TargetDiskMode.html

Testing Done Thus Far

• Hardware detection kit does not show the drive on the 1394 PCI bus slot, not useful for detecting hardware on the target machine, just the host.
• Disk wiping via Floe works well. Too well.
• Live Ubuntu or Debian boot detects the target drive
  • Should try this with a Mac with data on it to see how the live boot deals with the file system, should be fine
• I installed the pre-seeded network image to an Intel Core 2 Duo iMac, and it will not boot
  • Will see if installing via CD works any better (Intel Macs should be able to do this just fine, PPCs will be tricky because the host machine has to be able to boot from this disk too, I imagine there won't really be instances where this is an issue).

Installing Ubuntu onto an Intel Mac via TDM

• Turn the target Mac off
• Connect the target Mac via firewire to a Linux box or another Mac
• Figure out what kind of bootable media you want to use for the host computer (insert a disk into optical drive, make sure the external drive you want to boot from works, check your boot order, etc)
• Turn the target Mac on while holding down the T key
• The target screen should switch to a blue screen saver with a yellow firewire symbol
• You should be able to read the target drive from the host computer Disk Utility app
• Reboot the host computer and select the boot option you want to use
• Be sure to select the correct hard drive during the installation or you will loose everything on the host computer

Need instructions for EFI-based systems

testing with rEFIT

Need instructions for UEFI-based systems

seems to work with preseeded image

Need instructions for PPC-based systems