Installation Guide, Fifth Edition - HP 9000 rp7420 Server

Chapter 1
Introduction
Detailed HP 9000 rp7420 Server Description
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Figure 1-7 shows a simplified view of the memory subsystem. It consists of two independent access paths,
each path having its own address bus, control bus, data bus, and DIMMs. In practice, the CC runs the two
paths 180 degrees out of phase with respect to each other to facilitate pipelining in the CC. Address and
control signals are fanned out through register ports to the synchronous dynamic random access memory
(SDRAM) on the DIMMs.
Figure 1-7 Memory Subsystem
PDH Riser Board
The Platform Dependant Hardware Riser board is a daughter card for the cell board. It contains a
micro-processor memory interface microcircuit, processor-dependent hardware including the
processor-dependent code (PDC), flash memory, and a manageability microcontroller, called the Platform
Dependant Hardware Controller (PDHC) with associated circuitry. The PDH obtains cell board configuration
information from cell board signals and from the LPM on the cell.
The PDH riser board contains circuitry that the Cell board requires to function and, therefore, each cell board
must have a PDH Riser installed before it is added to a server.
Central Processor Units
The cell board can hold up to eight (four dual-core) CPUs and can be populated with CPUs in increments of
two CPUs. On a cell board, the processors must be the same type and speed. Two CPUs is the minimum
configuration allowed on the HP 9000 rp7420 Server. There are two Frontside Buses (FBS), one for sockets 0
and 1, and one for sockets 2 and 3. Each FBS must have either a CPU or a terminator at the end of the bus or
PDH Riser
Board
DIMM
Buffer
Address/
Controller
Buffer
Buffer
DIMM
DIMM
DIMM
QUAD 3
Cell
Controller
DIMM
DIMM
BufferBuffer
DIMM
DIMM
QUAD 2
To Quad 2 Address/Controller Buffers To Quad 3 Address/Controller Buffers
CPU 3
Front Side Bus 1
CPU 2
Front Side Bus 0
CPU 1 CPU 0
Buffer
DIMM
DIMM
DIMM
DIMM
Buffer
QUAD 0
To Quad 0 Address/Controller Buffers To Quad 1 Address/Controller Buffers
Buffer
DIMM
Buffer
Address/
Controller
DIMM
DIMM
Buffer
QUAD 1
DIMM
Address/
Buffer
Controller
Address/
Controller
Buffer