Compaq AlphaServer ES40 Manuel d'utilisateur télécharger pdf (Page 6)

Architecture

This system is designed to maximize the potential of the Alpha

21264 chip. The traditional bus interconnect has been replaced

by a switch-based interconnect system. With a bus design, the

processors, memory, and I/O modules share the bus. As the

number of bus users increases, the transactions interfere with

one another, increasing latency and decreasing aggregate

bandwidth. However, with a switch-based system there is no

degradation in performance as the number of CPUs, memory,

and I/O users increase. Although the users increase, the speed

is maintained.

With a switch-based, or point-to-point interconnect, the

performance remains constant, even though the number of

transactions multiplies. The switched system interconnect uses

a set of complex chips that route the traffic over multiple

paths. The chipset consists of one C-chip, two P-chips, and

eight D-chips.

•

C-chip. Provides the command interface from the CPUs

and main memory. Although there is only one C-chip in

the system, it allows each CPU to do transactions

simultaneously.

•

D-chips. Provide the data path for the CPUs, main

memory, and I/O.

•

P-chips. Provide the interface to two independent 64-bit

33 MHz PCI buses.

This chipset is similar to that used in the AlphaServer DS20

system; however, this chipset supports up to four CPUs and up

to 32 Gbytes memory (16 GB available now). Interleaving

occurs when at least two memory arrays are used.

Two 256-bit memory buses support four memory arrays,

yielding a 5.2 Gbytes/sec system bandwidth. Transactions are

ECC protected. Upon the receipt of data, the receiver checks

for data integrity and corrects any errors.

System Block Diagram

C-chip

First

CPU

8 D-chips

P-chip

1 or 2

Memory

Arrays

Memory

Arrays

64 bit PCI

Command, Address, and Control lines for each Memory Array

Control lines for D-chips

Memory

Data

Bus

CPU

Data

Bus

CAPbus

PAD

Bus

PKW

1400A-99

1 or 2

CPUs

B-cache

1 2 3 4 5 6 7 8 9 10 11 ... 17 18

Commentaires sur ces manuels

Pas de commentaire

Compaq AlphaServer ES40 Manuel d'utilisateur Page 6

Commentaires sur ces manuels

Produits connexes et manuels pour Serveurs Compaq AlphaServer ES40