FUJITSU SPARC ENTERPRISE M8000 - Manual (Page 460)

B-14 SPARC Enterprise M8000/M9000 Servers Service Manual • August 2009
B.9 Crossbar Unit
A crossbar unit (XBU: formal abbreviation is XBU_B) is mounted only in the SPARC
Enterprise M9000 server. The XBU consists of a connector and a crossbar switch
(XB). The connector is used to physically connect a CMU and IOU, and the XB
switches logical connections and controls data transfer between the CMU and IOU.
Up to eight XBUs can be mounted in a cabinet.
FIGURE B-9 shows the XBU_B.
FIGURE B-9 Crossbar Unit (XBU_B)
The XBU has the following characteristics.
■ Only cold replacement is available for the XBU.
■ In the SPARC Enterprise M9000 server (with an expansion cabinet) model, control
over the expansion cabinet is done by connecting the XBUs of both base cabinet
and expansion cabinet with cables.