Chapter 4 PA-RISC Computer Systems - OpenPA.net

HP N4000 (rp7405/rp7410) Internals
Buses
� Runway+/Runway DDR CPU bus (CPU to cell controller), 125 MHz DDR, 64-bit wide, 2.0 GB/s
per CPU — aggregate 8.0 GB/s for each cell (four CPUs/cell) and 16.0 GB/s for maximum system
� Memory bus (memory to cell controller) 4.0 GB/s for each cell — aggregate 8.0 GB/s for maximum
system
� XBC cell-to-cell link (cell controller to cell controller) 8.0 GB/s aggregate
� SBA cell-to-I/O link (cell controller to I/O backplane) 2.0 GB/s on each cell — aggregate 4.0 GB/s
for maximum system
� 32 I/O links/ropes, 12-bit wide, 265 MB/s (16 links/ropes on each cell) — 8.5 GB/s I/O aggregate
peak bandwidth
� 14 PCI-64/66 I/O buses for expansion slots
� Two PCI-64/33 I/O buses for expansion slots (for Core I/O SCSI/LAN)
� Two PCI-64/33 I/O buses for Core I/O (MP/SCSI)
� Two SCSI-3 Ultra160 LVD main storage I/O buses (one on each cell)
� Ultra SCSI SE for removable media (DVD/Tape)
Memory
� ECC DIMMs, low-voltage TTL interface, 125 MHz frequency (traditional/PC-133 SDRAMs do
not work)
� 256 MB, 512 MB and 1 GB modules supported (2 GB probably later too)
� 16 slots on each cell board (32 slots maximum in a full system configuration), installed in quads
� 32 GB maximum (in a full system configuration with two cells)
� 64 GB was given as maximum with “future” memory modules — probably working today
Expansion
There are in all 16 PCI 64-bit/66 MHz slots in the I/O cage, which can be fully accessed when using a
system with two cells — with one cell board only seven slots are available. One PCI slot is dedicated to
the Core I/O card set (see above) so only 15 of the 16 PCI slots are available for expansion options.
� 14 “Twin-Turbo” PCI 64-bit/66 MHz slots, each on an independent PCI bus, each connected via
two I/O links/ropes (aggregate 530 MB/s), hot-plug capable
� Two “Turbo” PCI 64-bit/66 MHz slots, each on an independent PCI bus, each connected via one
I/O link/rope (265 MB/s), hot-plug capable (one of these two Turbo slots is reserved for Core I/O
LAN/SCSI)
� Twelve slots keyed for 3.3 V (support either 3.3 V or universal PCI cards)
� Four slots keyed for 5.0 V (support either 5.0 V or universal PCI cards)
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