Lenovo ThinkStation P920 Manual page 5

How to Utilize the Onboard Intel SATA Controller
In the P920 system, drives are always connected through a backplane called
Blind Connect Assembly (BCA). When using the onboard Intel SATA controller,
up to four drives can be connected to the first (bottom) BCA and up to two drives
can be connected to the second (top) BCA. This gives the P920 support for up to
6 drives with the onboard Intel SATA controller via two BCA's.
The red boxes in the diagram below show the active SATA ports that are available
with the onboard Intel SATA controller.
Power 2
connect
or
BCA2 Control
connector
Power 1
connect
BCA1 Control
or
S/X 1 S/X 2
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