PCI and Cardbus drive controllers
The second generation PowerMac series, between the Nubus PowerMacs and the G3s, continue the earlier Apple practice of supporting only SCSI hard drives on the motherboard. The exceptions are such models as the Performa 5400, 5500, 6360 and so on, which allow a 'single' IDE hard drive, but still require a SCSI optical drive.
This presents a problem when replacing old, small or failed SCSI drives. Unlike the workarounds required for 68k Macs and Nubus PowerMacs, the problem is easily overcome by using a PCI drive controller.
PCI drive controllers support a variety of drive formats, from IDE/ATA, to ATAPI, SCSI (on HD50 and 68 pin connectors), SATA (including eSATA), Firewire, and USB. Support in OS 9 is variable; for example, USB cards are restricted to USB 1.1 speeds (12Mbit/s). In addition, as per usual with Mac expansion cards, it is necessary to ensure Mac compatibility of the specific card before purchase.
Further information on types of cards, and specific cards, will be added below. In the meantime, search the 68kmla forums for more advice.