There is a limitation in Mac OS 9.x that will not recognize a system on a volume larger than 190GB.
Backup any data you do not want to lose. Reinitialize the drive and partition it. Be sure that there is at least one volume smaller than 190GB for Mac OS 9.x to be installed on. Once this is done, there will be no problem booting.
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.