The Fusion D400Q and R400Q must have a hard drive in drive bay 1 when connected via USB, FireWire, or FireWire 800. This requirement is due to the Oxford bridge chip that controls USB and FireWire connectons. Drive bay 1 is the top bay in the Fusion D400Q and the left bay in the Fusion R400Q. As long as there is a drive in drive bay 1, bays 2-4 are unconstrained.
Note: This requirement does not apply to a direct SATA connection, which has no drive bay population requirements.
When attempting to connect a Sonnet Tempo eSATA locking cable to a Tempo SATA E4P card in an Xserve, the locking connector housing may not fit in the tight space at the rear of the Xserve. To properly connect the cable, simply remove the locking housing from the connector end (two screws) and it will fit.
