Clock+ Board

The clock+ board is located at the rear of the cabinet, at the right side of the card cage. See Figure B-12.

The clock+ board receives cooling air from the PCM located above the two board slots on the right side of the card cage.

The clock+ board provides 16 pairs of system clocks, 32 pairs of processor clocks.

The processor clock frequency is set to match the lowest-frequency processor in the system. All processors run at the same clock speed. The system clock and the processor clocks are derived from a single clock source. The frequency of the clock source as well as the processor and system clocks are programmable and set by firmware.

The clock+ board also includes central devices including serial ports, keyboard and mouse, and a time of day (TOD) chip.

Figure B-12 Clock+ Board