The dual SCSI implementation on the Quadra 900 means several things:
- Because the SCSI chains are electrically separate, there won't be any
interruption on the internal chain if something goes wrong on the
external chain (like a disconnect while the computer is on, poor
termination schemes, and so on).
- It gives third parties (and potentially Apple) the opportunity to
implement disk arrays using the two chips. Micronet is advertising
their Raven array without using two NuBus slots.
- You can assure speed of the drive internally using the internal cabling,
and not limit the speed of a drive by the cable you use (frayed cables,
bad cables, and so on).