1.1 Parallel Disk Array Components
1.1.3.1 DA Controller Interconnect
The front of the DA backplane provides connections for two sets of cables from
the DA controller backplane:
• 34-pin command cables
• 20-pin data cables
1.1.3.2 Disk Canister Interconnect
Disk canisters plug directly into the 64-pin connectors. (Sixty pins are used.)
The 4-pin power connectors supply DC voltage to the disk canisters. The DA
backplane interconnects support 20 disk canisters (19 canisters are used) with
the following:
• Disk signals to/from backplane
• Disk-to-disk signals (spindle lock)
• Disk power signals
1.1.3.3 Multiplexer Interconnect
The MUX PCBs plug directly into the DA backplane 64-pin connectors.
Read/write data and clocks, disk-selected, and command-complete signals route
here from the DA controller interconnects and from the disk interconnects. Status
lines to the lightpipe interconnects originate here.
The DA backplane interconnects provide 10 MUX PCBs with the following:
• Data to/from the disk
• Data to/from the controller
• Drive status signals to the lightpipe and disk-panel indicators
1.1.3.4 Lightpipe Interconnect
The DA backplane has two 10-pin lightpipe connectors. The split ribbon cable
carrying disk status signals to the lightpipe has two separate 10-pin connectors
at one end and a single 50-pin connector on the other, which connects to the
PDA front panel lightpipe. Each lightpipe connector is dedicated to signals from
one side of the DA backplane. For more detail on the lightpipe displays, refer to
Chapter 6.
1.1.3.5 Power Interconnect
A system of bus bars supplies the necessary DC voltage to the +12 VDC, +5 VDC,
and ground planes within the DA backplane. A 4-pin connector provides power to
the disk.
A 4-pin connector provides the sense line connection back to the power supply.
Parallel Disk Array Overview 1–11
