7. System configurations

Plug and Play requirements exist for three possible configurations:

a. Internal configuration - all SCSI peripheral devices are internal to the host enclosure.

b. External configuration - all SCSI peripheral devices are external to the host enclosure.

c. Mixed configuration - a combination of internal and external SCSI peripheral devices.

Each of these configurations exist for two design alternatives: add-in SCSI and motherboard SCSI. The term host adapter is used to refer to either the SCSI add-in card for the add-in SCSI design alternative or the SCSI logic within the host for the motherboard design alternative.

PnP SCSI host adapters that support a mixed configuration shall have an automatic switchable terminator at the exit point.

PnP SCSI peripheral devices shall not terminate the SCSI bus.

PnP SCSI peripheral subsystems attached to the SCSI bus shall be terminated by installing an external terminator into the remaining open connector on the last peripheral subsystem on the bus.