HP 9000 V-Class Manual

Operator’s Guide
HP 9000 V-Class Server
First Edition
A3725-96005
Customer Order Number: A3725-90005
October 1997
Printed in: USA

Revision History
Edition: First
Document Number: A3725-96005
Notice
Copyright Hewlett-Packard Company 1997. All Rights Reserved.
Reproduction, adaptation, or translation without prior written
permission is prohibited, except as allowed under the copyright laws.
The information contained in this document is subject to change without
notice.
Hewlett-Packard makes no warranty of any kind with regard to this
material, including, but not limited to, the implied warranties of
merchantability and fitness for a particular purpose. Hewlett-Packard
shall not be liable for errors contained herein or for incidental or
consequential damages in connection with the furnishing, performance
or use of this material.
FCC Notice
This equipment has been tested and found to comply with the limits for a
Class A digital device, pursuant to Part 15 of the FCC Rules. These
limits are designed to provide reasonable protection against harmful
interference when the equipment is operated in a commercial
environment.

This equipment generates, uses, and can radiate radio frequency energy
and, if not installed and used in accordance with the instruction manual,
may cause harmful interference to radio communications. Operation of
this equipment in a residential area is likely to cause harmful
interference, in which case the user will be required to correct the
interference at his own expense.
The user is cautioned that changes or modifications not expressly
approved by the party responsible for compliance (Hewlett-Packard)
could result in the equipment being noncompliant with FCC Class A
requirements and void the user’s authority to operate the equipment.
Do not connect external equipment to the utility outlets in the Hewlett-
Packard V-Class server. Unauthorized connection voids all agencies’
emissions certification.

Table of Contents v
Contents
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xiii
Notational conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xiii
1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
The PA-8200 processor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
The node. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
Control and status registers (CSRs) . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Description of functional blocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Processor agent controller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
Hyperplane crossbar—routing attachment controller . . . . . . . . . . . .6
Memory access controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Utilities board and core logic bus. . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
Node configurations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Shared memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10
2 Indicators, switches, and displays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Operator panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Key switch panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Key switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
DC ON LED. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
TOC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16
CDROM drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Busy indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Eject button . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Emergency eject. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18
Optional DAT drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Eject button . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
System Displays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
LCD (liquid crystal display). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Attention light bar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
3 Teststation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Teststation features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Teststation functionality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Teststation logons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Teststation sppuser windows. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Message window (test station console - message output) . . . . . . . . .29

vi Table of Contents
Console window (sppconsole - complex console). . . . . . . . . . . . . . . . 29
tcsh shell windows (tcsh). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Using the mwm Root Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Using the console . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Starting the console . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Using the Root Menu. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Using the sppconsole command . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Logging out. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Accessing the console remotely . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Watching the console remotely . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Display a list of other console users . . . . . . . . . . . . . . . . . . . . . . . 35
Controlling the console remotely . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Changing a console’s connection. . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Accessing system logs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Teststation file system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
/spp/etc. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
/spp/bin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
/spp/scripts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
/spp/data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
/spp/firmware. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
/spp/est. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
/spp/man . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
4 Firmware (OBP and PDC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Boot sequence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Boot process output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
HP mode boot menu. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Enabling Autoboot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Examples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
HElp command. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Syntax . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Examples. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
5 Starting and stopping HP-UX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Starting your HP 9000 V-Class Server . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Starting HP-UX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
HP-UX boot process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Reviewing the state of the file system . . . . . . . . . . . . . . . . . . . . . . . . . 56
Restarting HP-UX. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Restarting HP-UX from single-user mode . . . . . . . . . . . . . . . . . . . . 57
Restarting HP-UX from multiuser mode . . . . . . . . . . . . . . . . . . . . . 58

Table of Contents vii
Stopping HP-UX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59
Shutdown considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .59
Rebooting or shutting down the system . . . . . . . . . . . . . . . . . . . . . . . .60
6 Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
Configuring a PowerTrust UPS on
V-Class systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .62
Monitoring the PowerTrust UPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .63
If ac power fails . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64
ac power failure with automatic shutdown enabled. . . . . . . . . . . . . . .64
If ac power does not return. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64
If the unit nears full battery discharge . . . . . . . . . . . . . . . . . . . . . . .65
ac power fails without automatic shutdown enabled. . . . . . . . . . . . . .65
If you anticipate a long power outage . . . . . . . . . . . . . . . . . . . . . . . .65
If the unit nears full battery discharge . . . . . . . . . . . . . . . . . . . . . . .66
7 Recovering from failures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Collecting information. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68
Performance problems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .69
System hangs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70
System panics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .72
Peripheral problem. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73
Interface card and system problem. . . . . . . . . . . . . . . . . . . . . . . . . . . .74
File system problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75
LAN communication problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75
Logical Volume Manager (LVM) related problem. . . . . . . . . . . . . . . . .76
Recovery from other situations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76
Rebooting the system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77
Monitoring the system after a system panic. . . . . . . . . . . . . . . . . . . . .77
Abnormal system shutdowns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79
Fast dump. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79
Overview of the dump and save cycle . . . . . . . . . . . . . . . . . . . . . . . . . .80
Crash dump destination and contents . . . . . . . . . . . . . . . . . . . . . . . . .80
Configuration criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82
System recovery time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82
Dump level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82
Compressed save vs. noncompressed save . . . . . . . . . . . . . . . . . . .83
Using a device for both paging and dumping. . . . . . . . . . . . . . . . .83
Partial save. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83
Crash information integrity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85
Full dump vs. selective dump . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85
Dump definitions built into the kernel vs. defined at runtime . . .85

viii Table of Contents
Using a device for both paging and as a dump device . . . . . . . . . 86
Disk space needs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Dump level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
Compressed save vs. noncompressed save . . . . . . . . . . . . . . . . . . 87
Partial save (savecrash -p). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Defining dump devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
Kernel dump device definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
Using SAM to configure dump devices into the kernel . . . . . . . . 89
Using HP-UX commands to configure dump devices into the
kernel90
Runtime dump device definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
The /etc/fstab file. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
The crashconf command. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Dump order . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
What happens when the system crashes? . . . . . . . . . . . . . . . . . . . . . . 93
Operator override options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
The dump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
The reboot. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
savecrash processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Dual-mode devices (dump / swap) . . . . . . . . . . . . . . . . . . . . . . . . . 95
What to do after the system has rebooted? . . . . . . . . . . . . . . . . . . . . . 95
Using crashutil to complete the saving of a dump. . . . . . . . . . . . . . 96
Crash dump format conversion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
Analyzing crash dumps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99

List of Tables ix
Tables
Table 1 Node configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
Table 2 Indicator LED operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Table 3 Processor status codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Table 4 POST status codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
Table 5 HP-UX processor status codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Table 6 sppconsole commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34
Table 7 Boot menu commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47

xListofTables

List of Figures xi
Figures
Figure 1 Functional block diagram of a V-Class system . . . . . . . . . . . . . . . . . . . . . . . . . .4
Figure 2 ERAC interconnection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
Figure 3 Operator panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
Figure 4 Key switch panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15
Figure 5 CDROM drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17
Figure 6 DDS-3 DAT drive front panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Figure 7 System displays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
Figure 8 Front panel LCD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22
Figure 9 Teststation sppuser windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Figure 10 Teststation file system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
Figure 11 Boot process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43

xii ListofFigures

Preface xiii
Preface
The Operator’s Guide HP 9000 V-Class Servers documents the
information necessary to operate and monitor HP V-Class servers. This
book is not intended to be a tutorial but a reference for system
administrators, system operators, or system managers.
Notational conventions
This section describes notational conventions used in this book.
bold monospace In command examples, bold monospace
identifies input that must be typed exactly as
shown.
monospace In paragraph text, monospace identifies
command names, system calls, and data
structures and types.
In command examples, monospace identifies
command output, including error messages.
italic In paragraph text, italic identifies titles of
documents.
In command syntax diagrams, italic identifies
variables that you must provide.
The following command example uses
brackets to indicate that the variable
output_file is optional:
command input_file [output_file]
Brackets ( [ ] ) In command examples, square brackets
designate optional entries.
Curly brackets ({}),
Pipe (|) In command syntax diagrams, text surrounded by curly brackets indicates a
choice. The choices available are shown inside
the curly brackets and separated by the pipe
sign (|).
The following command example indicates
that you can enter either aor b:
command {a | b}

xiv Preface
Preface
Notational conventions
NOTE A note highlights important supplemental information.
CAUTION A caution highlights procedures or information necessary to avoid
damage to equipment, damage to software, loss of data, or invalid test
results.
Horizontal ellipses
(...) In command examples, horizontal ellipses show repetition of the preceding items.
Vertical ellipses Vertical ellipses show that lines of code have
been left out of an example.
Keycap Keycap indicates the keyboard keys you must
press to execute the command example.

Chapter 1 1
1 Overview
The V-Class server can contain four to 16 HP PA-8200, Precision
Architecture - Reduced Instruction Set Computer (PA-RISC) processors
and can support memory configurations of 256 Mbytes to 16 Gbytes.
This chapter provides a block diagram of the V-Class server and
discusses its features and configurations.

2Chapter1
Overview
The PA-8200 processor
The PA-8200 processor
The V-Class server uses the Hewlett-Packard PA-8200 processor, based
on the concept of Reduced Instruction Set Computers (RISC). The
PA-8200 was designed according to Hewlett-Packard’s PA-RISC
Architecture version 2.0 specifications.
The PA-RISC architecture is presented in the PA-RISC 2.0 Architecture
reference manual. Please refer to that document for detailed information
about the features of the PA-8200. This Operator’s Guide does not
attempt to duplicate information in that manual. Instead, it presents
only V-Class server-specific information.
The processors of the system are supported by several Application
Specific Integrated Circuits (ASIC) hardware controllers, an enhanced
memory system, and a high-bandwidth I/O subsystem. Special hardware
and software allow these processors to perform both as conventional
single CPUs or together, in parallel, to solve more complex problems
requiring parallel processing.

Chapter 1 3
Overview
The node
The node
The V-Class server can contain four to 16 processors. The terms node and
system are used interchangeably in this book. The node uses a
symmetric multiprocessor (SMP) design that can exploit fine-grain
parallelism.
A conceptual block diagram of the node is shown in Figure 1. Centrally
located in the diagram is the HP Hyperplane crossbar that is comprised
of four Exemplar Routing Attachment Controllers (ERAC). The
Hyperplane crossbar allows all of the processors to access all of the
available memory. Processors are installed on Exemplar Processor Agent
Controllers (EPACs). An EPAC allows the processor and the I/O
subsystem (the Exemplar PCI-bus Interface controller—EPIC) access to
the Hyperplane crossbar.
Also connected to the Hyperplane crossbar are the Exemplar Memory
Access controllers (EMAC). Up to two processors are located on each
EPAC. Memory is controlled by the EMAC. Input and output devices
connect to the node through EPIC which is connected to the processor
agents.
The Exemplar Core Utilities board (ECUB—commonly called the
Utilities board) in the node contains a section of hardware called the core
logic. It provides interrupts to all of the processors in the system through
the core logic bus which connects to each processor agent. The ECUB
attaches to the Exemplar Node Routing board (ENRB) centrally located
in the node.

4Chapter1
Overview
The node
Figure 1 Functional block diagram of a V-Class system
9/10/97
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Chapter 1 5
Overview
The node
Control and status registers (CSRs)
System hardware is manipulated by control and status registers, CSRs,
located in the processors and controllers.
CSRs provide control, status, or both to the processors and other
hardware in the node. Each CSR is memory mapped and is available to
all processors in the system. Many of the registers are described in detail
throughout this book by functional groups, such as system configuration,
messaging and data copy, error recovery, and so on.
Description of functional blocks
Each block in Figure 1 is described in the following sections.
Processor agent controller
The EPAC can connect to zero, one, or two PA-8200 processors. It can
also connect to zero or one EPIC (the I/O controller). With no processors,
the EPAC serves as an I/O-only interface. The EPAC has the following
buses:
Runway bus (0, 1)—Two each, 64-bit, bidirectional buses for processor 0
and processor 1, respectively. These buses have a raw bandwidth of 960
Mbytes/sec.
Hyperplane crossbar port bus (0, 1)—Four 32-bit, unidirectional buses
connected to two Hyperplane crossbar ERACs, two in each direction.
These buses have a total raw bandwidth of 1.9 Gbytes/sec.
I/O port—Two 16-bit or 32-bit, unidirectional interfaces to an I/O device,
one for reading data and one for writing data. The width of the bus
depends on the width of the I/O device connected. Each bus has a
bandwidth of 120 Mbytes/sec or 240 Mbytes/sec, depending on the width
of the interface.
Core Logic Bus interface—Bidirectional bus that supports boot and
support services.
The EPAC sends and receives transactions from the ERACs using four
unidirectional data paths. There are four ERACs in the Hyperplane
crossbar. Each processor agent, however, communicates with only two of
the four ERACs.

6Chapter1
Overview
The node
The EPAC includes special hardware called the data mover for rapid
message and data movement between memory within a node. This
dedicated hardware greatly improves file I/O and networking over
software versions.
Hyperplane crossbar—routing attachment controller
The Hyperplane crossbar is comprised of four ERACs that provide an
interconnect for each processor and I/O device to memory.
Each of the four ERACs has the following buses:
EPAC Port (A, B, C, D)—Eight 32-bit, unidirectional interfaces to four
EPAC ports, four in each direction. Each port has simultaneous (input
and output) bandwidth of 960 Mbytes/sec.
EMAC Port (A, B, C, D)—Eight 32-bit, unidirectional interfaces to four
EMAC ports, four in each direction. Each port has simultaneous (input
and output) bandwidth of 960 Mbytes/sec.
Figure 2 shows how the ERACs connect to each EPAC and EMAC.