Althought the TSATA supports booting from an attached drive, it does not support target disk mode when booting from an attached drive. Try connecting the two computers via ethernet to exchange files.
The Tempo SATA is bootable with Mac OS X. For some users the drive does not show up when the\u160 Mac OS X 10.5 (Leopard) DVD is inserted. This is a bug in the Leopard installer program.
In this case, using SuperDuper or Carbon Copy Cloner to clone the current boot drive to the\u160 hard drive on the Tempo SATA allows the drive to be seen by the Mac OS X installer.