Depending on their architecture, the worstations are likely to feature one of the following hard drive buses.
An SCSI connector is located at the rear of the Workstation; the SCA chanel is found on the internal bus of the SPARC Worstations, it can be basicaly seen as an SCSI bus that provides power supply and assigns SCSI ID to the peripherals.
This is found for example in an Ultra 5 or Ultra 10 workstations
It is used by the SunBlade 1000 workstation.