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Chapter 2 subsystem architecture and components, 1 overview – Compaq 9900 User Manual

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Hitachi Lightning 9900™ User and Reference Guide

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Chapter 2 Subsystem Architecture and Components

2.1 Overview

Figure 2.1 shows the Hierarchical Star Network (HiStar or HSN) architecture of the Lightning
9900™ RAID subsystem. The “front end” of the 9900 subsystem includes the hardware and
software that transfers the host data to and from cache memory, and the “back end”
includes the hardware and software that transfers data between cache memory and the disk
drives.

CHT

DTA

MPA

CHT

DTA

MPA

Data Cache

control cache

Data Cache

control cache

Data Cache

Data Cache

Cache Switch

Processor Side

Cache/Data Side

Cache Switch

Processor Side

Cache/Data Side

Cache Switch

Processor Side

Cache/Data Side

Cache Switch

Processor Side

Cache/Data Side

ACP

DTA

MPA

ACP

DTA

MPA

Figure 2.1

Lightning 9900™ HiStar Network (HSN) Architecture