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Document:	Digital StorageWorks Fiber-Optic UltraSCSI Extender (DWZGA) User's Guide
Order Number:	EK-DWZGA-UG
Revision:	A01
Pages:	50
Original Filename:

OCR Text

Fiber-Optic UltraSCSI
Extender (DWZGA)
User's Guide
EK–DWZGA–UG. A01

Digital Equipment Corporation
Maynard, Massachusetts

First Edition, February 1998
The information in this document is subject to change without notice and should not be
construed as a commitment by Digital Equipment Corporation.
Digital Equipment Corporation assumes no responsibility for any errors that might
appear in this document.
The software, if any, described in this document is furnished under a license and may
be used or copied only in accordance with the terms of such license. No responsibility is
assumed for the use or reliability of software or equipment that is not supplied by
Digital Equipment Corporation or its affiliated companies.

The following are trademarks of Digital Equipment Corporation:
Alpha, DEC OSF/1, Digital UNIX, OpenVMS, StorageWorks, and the Digital logo.
The following are third-party trademarks:
Microsoft and MS-DOS are registered trademarks, and Windows and Windows NT are
trademarks of Microsoft Corporation.
Intel, Intel486, and i486 are trademarks of Intel Corporation.
NetWare is a registered trademark of Novell, Inc.
SCO UNIX is a trademark of Santa Cruz Operations, Inc.
SIMM is a trademark of Wang Laboratories.
All other trademarks and registered trademarks are the property of their respective
holders.

 Digital Equipment Corporation 1998
Printed in the U.S.A.

Contents
Revision Record ................................................................................................................... v
About This Guide .............................................................................................................. vii
1

Introduction
1.1 Product Description................................................................................................ 1–1
1.1.1 Overview.......................................................................................................... 1–1
1.1.2 DWZGA Approach........................................................................................... 1–1
1.1.3 System Level Operation ................................................................................... 1–4
1.1.4 SCSI Configuration .......................................................................................... 1–4
1.1.5 Optical Data Link (ODL).................................................................................. 1–5
1.1.6 Special SCSI Considerations ............................................................................ 1–6
1.1.6.1 Target Selection Time-Outs.............................................................................. 1–6
1.1.6.2 Data Transfer Disconnect Control (DTDC)....................................................... 1–6
1.1.6.3 Selection/Reselection Collisions....................................................................... 1–6
1.1.6.4 SCSI Resets...................................................................................................... 1–7

1.2

Specifications......................................................................................................... 1–7

1.3

Switch Setting Tool................................................................................................ 1–8

1.4

Front Panel Equipment ........................................................................................... 1–9

1.5

Switch Setting Information................................................................................... 1–13

1.6

Rear Panel Equipment .......................................................................................... 1–15

Installation
2.1

Unpacking.............................................................................................................. 2–1

2.2

Tools Required....................................................................................................... 2–1

2.3

Cabling .................................................................................................................. 2–1

Configuration
3.1

Setting Switches on LOCAL Unit........................................................................... 3–1

3.2

Setting Switches on REMOTE Unit........................................................................ 3–2

3.3

Startup ................................................................................................................... 3–3

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DWZGA User’s Guide

Maintenance
4.1

Tools and Materials Required................................................................................. 4–1

4.2

Fiber-Optic Cable Connectors ................................................................................ 4–1

4.3 Fiber-Optic Port ..................................................................................................... 4–3
4.3.1 Air Duster ........................................................................................................ 4–4
4.3.2 Using In-House Air Supply .............................................................................. 4–4
4.3.3 Using Isopropyl Alcohol .................................................................................. 4–5

Troubleshooting
5.1

Equipment Required............................................................................................... 5–1

5.2

Procedure ............................................................................................................... 5–1

Appendix A Manufacturer’s Declarations
Readers Comment Form .........................................................................Inside Back Cover
Figures
1–1
1–2
1–3
1–4
2–1
2–2
2–3

DWZGA Unit......................................................................................................... 1–2
Switch Setting Tool................................................................................................ 1–8
Front Panel of DWZGA Unit.................................................................................. 1–9
Rear Panel of DWZGA Unit................................................................................. 1–13
Typical Fiber-Optic UltraSCSI Extender Configuration.......................................... 2–2
Cabling Typical Configuration ............................................................................... 2–4
Cabling with Terminator on One SCSI Port............................................................ 2–4

4–1 Cleaning Fiber-Optic Cable Connectors.................................................................. 4–2

Tables
1–1 DWZGA Unit Front Panel Descriptions................................................................ 1–10
1–2 DWZGA Unit Rear Panel Descriptions................................................................. 1–14
5–1 Troubleshooting Table............................................................................................ 5–1

EK–DWZGA–UG. A01

Revision Record
This Revision Record provides a concise publication history of this user’s guide. It lists
the guide’s revision levels, release dates, and reasons for the revisions.

The following revision history lists all revisions of this publication and their effective
dates. The publication part number is included in the Revision Level column, with the
last entry denoting the latest revision. This publication supports the StorageWorks
DWZGA Fiber-Optic UltraSCSI Extender.
Revision Level

Date

Summary of Changes

EK–DWZGA–UG. A01

February 1998

Original release

EK–DWZGA–UG. A01

About This Guide
This section defines the audience of the guide and describes its contents and structure.
In addition, this section identifies the conventions used in the guide.

The StorageWorks DWZGA Fiber-Optic UltraSCSI Extender User’s Guide
This guide describes the DWZGA and provides instructions for installing,
configuring, maintaining, and troubleshooting it.

Intended Audience
This guide is for system administrators and users who need to install, configure
and maintain the DWZGA.

Organization
This guide contains the following:
Chapter 1: Introduction
This chapter provides a description of the DWZGA and its application.
Chapter 2: Installation
This chapter contains instructions for unpacking DWZGA units and cabling two
DWZGA units to implement a typical, sample configuration. It also lists tools
required for the installation.
Chapter 3: Configuration
This chapter contains procedures for configuring the LOCAL and REMOTE
DWZGA units.
Chapter 4: Maintenance
This chapter contains procedures for cleaning the end faces on the fiber-optic
cable connectors of the fiber-optic link and the fiber-optic port on each DWZGA
unit.
Chapter 5: Troubleshooting
This chapter contains procedures for troubleshooting the fiber-optic UltraSCSI
extender.

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DWZGA User’s Guide

Appendix A: Manufacturer’s Declarations
This appendix contains the Radio Frequency Interference (RFI) declarations for
the fiber-optic UltraSCSI extender.

Conventions
This guide uses the following conventions:
Style

Meaning

boldface mono-space
type

To be input by the user

plain mono-space type

Screen text

italic type

For emphasis, manual titles, utilities, menus,
screens, and filenames

Special Notices
This guide uses the following to emphasize specific information.
WARNING
WARNING indicates the presence of a hazard
that can cause personal injury if the hazard is
not avoided.

CAUTION
CAUTION indicates the presence of a hazard
that might damage hardware or corrupt
software.
NOTE
Notes provide additional information.

Associated Documents

viii

Document Title

Order Number

Disaster Recovery Solutions Getting Started Guide

EK–SWXDR–GS. A01

EK–DWZGA–UG. A01

About This Guide

Support and Services
Who to contact in the Americas
Information and Product Questions:

Local Sales Office / StorageWorks Hotline
1-800-786-7967

Installation Support:

Contact the DIGITAL Distributor where the
Storage Solution was Purchased / Local Digital
Sales Office.

DIGITAL Multivendor Customer Service (MCS):
Installation

Contact the DIGITAL Customer Support Center
(CSC).

Warranty

Contact the DIGITAL Customer Support Center
(CSC) for warranty service after solution is in
stalled and operating.

Remedial

Contact the DIGITAL Customer Support Center
(CSC)
Note: A Service Contract is recommended when
the equipment is out of warranty. Contact the
local DIGITAL Sales Office.

Customer Support Center (CSC)

1 800-354-9000

Who to contact in Europe
Information and Product Questions:

Contact the DIGITAL Distributor or reseller

Installation Support, and Installation:

Contact the DIGITAL Distributor or reseller from
whom the Storage Solution was purchased.

For Warranty Service

See the Warranty Card packaged with the
product.

For Remedial Service

Contact the DIGITAL Distributor or reseller from
whom the Storage Solution was purchased.
Note: A Service Contract is recommended when
the equipment is out of warranty.

Who to contact in Asia Pacific
For all services, contact the DIGITAL Distributor or reseller from whom the
equipment was purchased.

AA–R07GA–TE

1
Introduction
This chapter provides a description of the DWZGA and its application.

1.1

Product Description
1.1.1 Overview
The Digital Equipment Fiber Optic UltraSCSI Extender, hereafter referred to as a
DWZGA unit, is used as an Ultra wide differential SCSI bus extender for
extending the length of a single SCSI bus up to 15 kilometers. (See Figure 1–1.)
Two DWZGA units are connected back-to-back with a long-distance fiber-optic
(FO) link between them. The DWZGA unit at each end of the FO link interfaces
to the SCSI bus with one DWZGA unit at the host end, the other at the device
end. The extender is transparent to the host and devices at both ends of the SCSI
bus.
DWZGA units are Pentium-based and equipped with Differential SCSI interfaces
and laser-based FO interfaces. Each DWZGA unit is packaged as a desktop
enclosure and includes a rack mounting kit for users who require, or prefer, rack
mounting.

1.1.2 DWZGA Approach
The simplest approach to interfacing extenders with SCSI buses is to pass signals
through boxes, attempting to create at a remote connector the signals present at a
local connector. The SCSI interface does not lend itself well to this approach for
several reasons:
1.

SCSI features which are important for overall system performance, such as
arbitration and disconnect/reconnect, are dependent on the total cable
lengths being short enough for control signals to reach all devices on the bus
within certain maximum times.

SCSI features which provide for more complex system architectures, such as
multi-initiator configurations, also depend on the cable length being short
enough for control signals to reach all devices within certain maximum
times.

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1–1

DWZGA User’s Guide

Figure 1–1 DWZGA Unit

S H R -!0 0 1

1–2

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Chapter 1. Introduction

Because SCSI data transfers are not protected by error codes, such as ECC,
it is critical that we have an effective method for protecting the validity of
data as it is transferred and converted; that is, differential SCSI to fiber
optic, fiber optic to differential SCSI.

Rather than serving as a simple electrical converter, the DWZGA uses industry
standard SCSI controllers to perform SCSI transactions at each DWZGA unit,
preserving the integrity of SCSI system timing requirements by establishing an
effective cable length that does not extend across the fiber, and is within the
SCSI specifications (25 meters for differential systems). The DWZGA unit
attached to a Host assumes the characteristics of a string of peripherals, while the
DWZGA unit attached to the remote string of peripherals assumes the
characteristics of a Host.
Additionally, DWZGA provides a number of features designed to ensure data
integrity during transfer, including:
1.

Every byte of data transferred by a DWZGA unit across the FO link is
echoed by the receiving unit and then checked against a copy of the data
which was sent. During SCSI reads, peripheral data is sent from the
REMOTE unit to the LOCAL unit, and echoed back to the REMOTE unit
for comparison. During SCSI writes, HOST data is sent from the LOCAL
unit to the REMOTE unit and echoed back to the LOCAL unit for
comparison. In order for a SCSI operation to complete successfully, all data
must match. Because the fiber optic interface is full duplex (data can be
transferred in both directions simultaneously) and the SCSI interface is half
duplex (data is only transferred in one direction at a time) there is no impact
on system performance.

All data buses are protected by vertical parity, as well as other circuitry
which detects conditions such as under/over-run.

The fiber optic interface uses 8B/10B encoding, and any single invalid code
detected by the fiber optic receiver will cause an operation to be flagged and
reported as being in error.

The transfer count in both DWZGA units (REMOTE and LOCAL) are
compared at the end of an operation, and must match.

At the end of each operation, the LOCAL DWZGA unit attached to the HOST
checks that no errors were reported by the peripheral, the REMOTE DWZGA
unit attached to the peripheral, or the LOCAL DWZGA unit itself. Any errors
detected are reported using standard SCSI check status/sense data reporting
techniques, and can therefore be diagnosed as required.

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DWZGA User’s Guide

1.1.3 System Level Operation
The following discussion of typical operations serves to illustrate how DWZGA
works at the system level.
The HOST selects the LOCAL DWZGA unit attached to it. Then the HOST
transfers a command to the selected LOCAL DWZGA unit. with the LOCAL
DWZGA unit acting as a string of peripherals. If the HOST allows disconnects,
the LOCAL DWZGA unit disconnects from the SCSI bus, allowing additional
SCSI commands to be transferred, either to different peripheral addresses or from
different initiators. Commands are immediately stored and forwarded from the
LOCAL DWZGA unit attached to the HOST to the REMOTE DWZGA unit
attached to the peripherals, then the peripherals are selected and the commands
transferred to them in the order received.
When a peripheral indicates it is ready for data transfer, either by responding
with data phase immediately following selection and command transfer, or after
a disconnect/reconnect sequence, the LOCAL DWZGA unit attached to the
HOST is instructed to reconnect to the appropriate HOST for data transfer. Once
all of the connections are in place (peripheral to REMOTE DWZGA, and
LOCAL DWZGA to HOST) data transfer is enabled. At this point, DWZGA
serves as a long data path, allowing data to flow through from HOST to
peripheral (SCSI write) or peripheral to HOST (SCSI read). SCSI data
handshakes are handled locally by each DWZGA unit, and do not extend across
the fiber, thereby eliminating potential performance impacts due to propagation
delays in driving control signals back and forth across the fiber, even when
transferring data asynchronously.
This flow-through technique is used rather than store-and-forward (as in the case
of SCSI commands) to avoid latency. This way, data transfer occurs in almost
the same time as with the peripheral directly connected to the HOST.

1.1.4 SCSI Configuration
A DWZGA link, two DWZGA units create one DWZGA link, can be inserted
anywhere in a typical SCSI cabling topology with one caveat: SCSI commands
can only be extended in one direction; that is, from a HOST, or HOSTS, at a
LOCAL DWZGA unit to a peripheral or peripherals at a REMOTE DWZGA
unit.

1–4

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Chapter 1. Introduction

Each DWZGA unit has a front panel with 4 switches for setting certain DWZGA
SCSI features, and 16 switches for setting the SCSI addresses of the targets
(peripherals) which are being extended by the DWZGA. Each of the 16 switches
represents one of the possible SCSI physical unit addresses in a wide SCSI
subsystem.
All Digital Equipment Corporation DWGZAs support both wide and narrow
SCSI buses as defined by the SCSI specifications, and will respond to
synchronous data transfer negotiations to a maximum rate of 20 million transfers
per second and a maximum offset of 16, and wide data transfer negotiations to a
maximum of 16 bits per transfer (ULTRA Wide). All other lesser negotiations,
such as slower synchronous, asynchronous, and narrow data transfers are also
supported.

1.1.5 Optical Data Link (ODL)
The DWZGA currently provides LASER-based ODL w/ Duplex SC connector.
The ODL uses a 1300nm wavelength. DIGITAL recommends singlemode fiber.
When choosing components for a laser-based cabling system using singlemode
fiber, ensure that all components are designed for use with singlemode cable (9
micron).

EK–DWZGA–UG. A01

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DWZGA User’s Guide

1.1.6 Special SCSI Considerations
1.1.6.1 Target Selection Time-Outs
When a DWZGA unit detects a selection time-out while attempting to select a
target, it will instruct the other DWZGA (attached to the HOST) to respond to
one additional SCSI command for that target address — which should be a
Request Sense in response to the check status returned for the original command
— and then not respond to that target address for a short period of time (10
seconds), causing a selection time-out at that target address for the HOST. This is
required by some systems which only recognize a target’s absence by selection
time-outs, as opposed to a reported Not Ready condition.
1.1.6.2 Data Transfer Disconnect Control (DTDC)
Because of the method employed by the DWZGA in establishing a flow-through
data transfer, the DWZGA will attempt to set the DTDC field in mode page 02
(Disconnect-Reconnect Page) to 01b for any device attached to the DWZGA
which reports itself to be a Direct Access Storage Device (disk drive), instructing
the peripheral not to disconnect in the middle of a data transfer. Note that the
peripheral may disconnect between command transfer and data transfer, and
between data transfer and ending status, thus ensuring support for performanceminded events such as overlapping seeks).
1.1.6.3 Selection/Reselection Collisions
It is possible, and in fact quite likely in systems with multiple targets, that an
initiator could select a LOCAL DWZGA at the same time that a target has
reselected a REMOTE DWZGA for data transfer. In most, cases, the LOCAL
DWZGA will simply accept and queue the incoming SCSI command,
disconnect, and then reconnect to the appropriate initiator for the data transfer
which is indicated by the target’s reconnection to the REMOTE DWZGA.
In the case where an initiator has selected a LOCAL DWZGA without allowing
disconnects (by setting Disconnect OK [DOK] false in the identify message), the
LOCAL DWZGA will return busy status to the initiator so that it may then begin
arbitration for the bus and subsequent reconnection for data transfer with the
target. The initiator should re-attempt the selection after the subsequent
reselection.

1–6

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Chapter 1. Introduction

1.1.6.4 SCSI Resets
SCSI resets which are detected at a DWZGA unit are propagated across the fiber
to, and regenerated by, the other DWZGA unit. Additionally, a DWZGA unit
may generate its own SCSI reset to recover from serious error conditions.

1.2

Specifications
Characteristic

Value
SCSI

Number of channels:

Maximum data rates:

10 MB/sec, 8-bit synchronous
20 MB/sec, 16-bit synchronous
5 MB/sec, 8-bit asynchronous
10 MB/sec, 16-bit asynchronous

Bus width:

Narrow, 8-bit or wide, 16-bit

Electrical:

Differential

Connector:

(2) 68-pin high density SCSI P-type
(female)

Termination:

External differential
Terminator power optionally supplied by
DWZGA unit.

Fiber
Type:

9 micron/1300nm singlemode

ODLs/connectors:

1300 nm laser/duplex SC

Encoding:

8B/10B

Data rate:

260 MBaud/ 26 MB/sec maximum

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1–7

DWZGA User’s Guide

Characteristic

Value
Platform

Processor:

Intel Pentium

Power supply:

100 – 120V ac, 6-amp maximum, or
200 – 240V ac, 4-amp maximum;
switch selectable

Dimensions:

6.5 in., height
16.5 in., width
17.0 in., depth

1.3

KVA:

0.360

BTU:

1200

Switch Setting Tool
Figure 1–2 shows the switch setting tool supplied with each DWZGA unit. Use
this tool to set the rocker-type DIP switches mounted behind holes drilled in the
front panel of each DWZGA unit. Insert the switch setting tool into the desired
hole and push until you feel the switch move and the associated front panel LED
change. If the switch doesn’t move easily, do not force the tool into the hole.
Instead, move the tool to align it with the switch.
If the switch setting tool is unavailable, a paper clip may be substituted. Re-form
the exposed end of the paper clip 90 degrees and insert the re-formed end into
the desired hole.
Figure 1–2 Switch Setting Tool

1–8

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Chapter 1. Introduction

1.4

Front Panel Equipment
Figure 1–3 shows the front panel of a DWZGA unit containing switches, LED
indicators, and a floppy diskette drive. Numbered callouts on Figure 1–3 are
keyed to the descriptions in Table 1–1.
Figure 1–3 Front Panel of DWZGA Unit

S H R -1 0 0 2

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1–9

DWZGA User’s Guide

Table 1–1 DWZGA Unit Front Panel Descriptions
No.

Designation

State

Description

PUSH TO SET

Pressed

4 rocker-type DIP switches — Each switch
enables an associated function described
below (No. 2, 3, 4, and 5) and lights that
function’s LED indicator adjacent to the
switch.

PUSH TO CLEAR

Pressed

Disables associated function and turns off
its adjacent LED indicator.

TPWR

LED indicates DWZGA-supplied diodeprotected terminator power enabled when
associated PUSH TO SET switch is
pressed. (See No. 9, below.)

Off

Indicates DWZGA-supplied diode-protected
terminator power disabled when associated
PUSH TO CLEAR switch is pressed. (See
No. 9, below.)

LED indicates DWZGA-initiated wide data
transfer request enabled when associated
PUSH TO SET switch is pressed

Off

Indicates DWZGA-initiated wide data
transfer request disabled by pressing PUSH
TO CLEAR switch

LED indicates DWZGA-initiated
synchronous data transfer request enabled
when associated PUSH TO SET switch is
pressed.

Off

Indicates DWZGA-initiated synchronous
data transfer request disabled when
associated PUSH TO CLEAR switch is
pressed.

LED indicates DWZGA unit attention
request enabled when associated PUSH TO
SET switch is pressed (target role). Can
also show special DWZGA data transfer
disconnect control (initiator role)

Off

Shows DWZGA unit attention request
disabled when associated PUSH TO
CLEAR switch is pressed (target role). Can
also show standard DWZGA data transfer
disconnect control (initiator role)

1–10

WIDE*

SYNC*

UA/DISC*

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Chapter 1. Introduction

Table 1–1 DWZGA Unit Front Panel Descriptions (Cont.)
No.

Designation

State

Description

DIFFSENSE

LED indicates single-ended device connected
to differential SCSI bus. DWZGA drivers are
disabled. Situation must be corrected.

DIFFERENTIAL

LED indicates DWZGA is configured for use
on differential SCSI bus. This configuration is
factory set and cannot be field modified.

SINGLE-ENDED
(not used)

Off

LED off to be consistent with DIFFERENTIAL
LED on, above. (If on, LED would indicate
DWZGA unit incorrectly configured at factory
for single-ended SCSI bus.)

TERMPOWER

LED indicates that DWZGA detects SCSI
terminator power.

TARGETS

LEDs 0 through 15 driven directly from
associated switches. Each LED indicates
corresponding PUSH TO SET target ID switch
is pressed. (See No. 15.)

Off

Each unlit LED indicates its corresponding
PUSH TO CLEAR switch is pressed.

POWER

LED indicates DWZGA unit power is on. (See
No. 16, below.)

FIBER

Off

LED indicates no fiber-optic power detected.
DWZGA units load firmware from floppy
diskette. (See No. 17, below.) Within 60
seconds of turn on, DWZGA should be
operational and LED indicates state of
DWZGA unit’s connection to other DWZGA
unit as follows:

Blinks 1x

Fiber-optic power detected — waiting for
receiver synchronization.

Blinks 2x

Fiber-optic power detected and receiver
synchronized — waiting for fiber interface
state change.

Blinks 3x

Other DWZGA unit reporting itself nonoperational.

Blinks 4x

Other DWZGA unit reporting itself off-line.

Blinks 5x

Other DWZGA unit resetting its fiber-optic
interface.

Blinks 6x

Waiting for fiber-optic interface reset to
complete.

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1–11

DWZGA User’s Guide

Table 1–1 DWZGA Unit Front Panel Descriptions (Cont.)
No.

Designation

State

Description

FIBER (cont.)

On (solid)

Power on self test successfully
completed.

ACTIVE

LED indicates DWZGA unit is initiating
commands, responding to commands,
or transferring data

ERROR

LED indicates an internal DWZGA unit
error has occurred.

TARGETS PUSH TO
SET

Pressed

15 rocker-type DIP switches tell the
initiators attached to the DWZGA unit
which target ID addresses are attached
to the DWZGA unit on the other side of
the fiber. Each switch lights a
corresponding target ID indicator. (See
No. 10, above.)

TARGETS PUSH TO
CLEAR

Pressed

Each switch turns off its associated LED
to show the state of switch and deselect
the DWZGA unit initiator for that target
ID.

(Power Switch)

Pressed to
on

Alternate action push-button switch
connected to ac source in series with
1/0 rocker-type switch on rear panel —
Energizes DWZGA unit when 1/0 switch
is at 1 (on).

(Floppy Drive)

––

3.5-in. floppy diskette drive used for
firmware diskette — DWZGA unit may
be started by pressing power switch on
with firmware diskette in drive. Firmware
will load automatically and DWZGA unit
will be fully operational in 60 seconds.

*See section 1.5, Switch Setting Information for recommendations.

1–12

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Chapter 1. Introduction

1.5

Switch Setting Information
DIGITAL strongly recommends setting SYNC to on, WIDE to on, and UA/DISC
to off for all applications. Other settings may be used with older target
equipment; that is, disk and tape drives, but efficiency may be degraded.
Table 1–2 provides additional information on the SYNC and WIDE settings for
both LOCAL and REMOTE DWZGA units.
Table 1–3 provides additional information for UA/DISC settings. As defined in
the table, the effect of these settings differs with application; that is, whether the
DWZGA unit is used as a LOCAL or REMOTE.
Table 1–2 SYNC and WIDE Switch Settings for Both LOCAL and REMOTE
DWZGA Unit Applications
Switch

Position

Effect

SYNC

DWZGA unit can initiate data transfer in synchronous
mode, or support it if initiated elsewhere.

Off

DWZGA unit cannot initiate data transfer in
synchronous mode, but can support synchronous
mode if initiated elsewhere.

DWZGA unit can initiate wide data transfer and
support wide data transfer if initiated elsewhere.

Off

In combination with SYNC off (SYNC off / WIDE off),
DWZGA unit supports wide data transfer if initiated
elsewhere.

WIDE

In combination with SYNC on (SYNC on / WIDE off),
DWZGA unit completely disables wide data transfer,
and does not support wide data transfer if initiated
elsewhere. This combination (SYNC on / WIDE off),
could be useful when a wide device is configured into
a narrow cabling scheme.

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1–13

DWZGA User’s Guide

Table 1–3 Unit Attention/Disconnect Control (UA/DISC) Switch Settings for
Both LOCAL and REMOTE DWZGA Unit Applications
DWZGA
Unit
Application

UA/DISC
Switch
Position

LOCAL

Effect
Unit Attention feature of switch — DWZGA reports
unit attention check on DWZGA power cycle; that is,
when DWZGA is powered off, then on again. UA
report helps recovery from power cycle, but can be a
problem if target also issues UA.
Disconnect Control feature of switch — Prevents
DWZGA unit from disconnecting regardless of state
of disconnect bit in identification (ID) message.
Forces input/output (I/O) from HOST to be single
threaded.

Off

Unit Attention feature of switch — DWZGA does
not report unit attention check on DWZGA power
cycle. Allows target-initiated negotiation to reestablish coordinated state with first command
issued.
Disconnect Control feature of switch — DWZGA
passes on disconnect bit in ID message, thereby
permitting disconnection for increased data transfer
efficiency.

1–14

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Chapter 1. Introduction

Table 1–3 Unit Attention/Disconnect Control (UA/DISC) Switch Settings for
Both LOCAL and REMOTE DWZGA Unit Applications (Cont.)
DWZGA
Unit
Application

UA/DISC
Switch
Position

REMOTE

Effect
Unit Attention feature of switch — Has no effect on
REMOTE DWZGA.
Disconnect Control feature of switch — DWZGA
disables disconnect bit in ID message. This permits
disconnection and allows multiple operations from
HOST to LOCAL side DWZGA, but single threads I/O
from REMOTE DWZGA to target.

Off

Unit Attention feature of switch —DWZGA does
not report unit attention check on DWZGA power
cycle. Allows target-initiated negotiation to reestablish coordinated state with first command
issued.
Disconnect Control feature — DWZGA unit passes
on disconnect bit in ID message, thereby permitting
disconnection to allow multiple operations and
improve data transfer efficiency.

1.6

Rear Panel Equipment
Figure 1–4 shows the rear panel of a DWZGA unit containing switches,
connectors, and an LED indicator. Numbered callouts on Figure 1–4 are keyed to
the descriptions in Table 1–4.

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1–15

DWZGA User’s Guide

Figure 1–4 Rear Panel of DWZGA Unit

S HR -100 4

1–16

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Chapter 1. Introduction

Table 1–4 DWZGA Unit Rear Panel Descriptions
No.

Designation

State

Description

AC POWER INLET

––

Connector receptacle — Accepts power
cord supplied with each DWZGA unit to
connect unit to a 100 – 120V ac, 6-amp
maximum, or 200 – 240V ac, 4-amp
maximum power source.

115/230

115

Voltage selector slide switch — Notch at
115 designates 115V position. Switch is
factory set to this position to power DWZGA
unit from a 115V ac source

230

Moving notch to 230 position conditions
DWZGA unit for 230V ac source.

1 (on)

Rocker-type switch supplies ac power to
power switch on DWZGA unit front panel.
(See section 1.5.)

0 (off)

Removes ac power, and therefore on/off
power control, from power switch on front
panel.

1/0 (Power Switch)

(SCSI Connectors)

––

2, 68-pin high-density SCSI P-type, female
SCSI connectors

(Fiber-Optic Port)

––

Duplex SC connector equipped with
removable rubber plug — Designed to
accept laser-based optical data link (ODL),
1300-nanometer wavelength, singlemode
cable with 9-micron core diameter —
polarization of the fiber-optic connector
ensures correct connection.

(Red LED)

Indicates that module within DWZGA unit is
operational with no problems.

Off

When DWZGA unit is energized, indicates
that module is defective, or fiber link is
open.

––

8 connectors presently unused: audio,
microphone input, keyboard, mouse,
communications 1, communications 2,
parallel, and video

AUDIO
MIC IN
KEYBD
MOUSE
COM 1
COM 2
PARALLEL
VIDEO

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1–17

2
Installation
This chapter contains procedures for unpacking and cabling the LOCAL and REMOTE
DWZGA units. It also lists tools required for the installation.

2.1

Unpacking
Inspect the package to ensure it contains a DWZGA unit, power cord, switch
setting tool, SCSI bus terminator, firmware diskette, diagnostic diskette and
user’s guide. Contact the distributor for a replacement if any item is missing or
damaged.

2.2

2.3

Tools Required
•

Switch setting tool for operating PUSH TO SET/PUSH TO CLEAR switches
on DWZGA unit front panel — If you misplace this tool, substitute a re-formed
paper clip as explained in section 1.3, Switch Setting Tool.

•

Small, slotted-head screwdriver for connecting and removing SCSI
connector(s) and terminator

Cabling
Figure 2–1 shows a typical fiber-optic UltraSCSI extender configuration. The
following procedure contains the cabling required to implement this
configuration. The LOCAL and REMOTE DWZGA units are physically
identical, but configured differently. You may need to modify the procedure to
match your own configuration.
NOTE
If necessary, identify controls, connectors, and
indicators specified in the following procedures by
referring to sections 1.4, Front Panel Equipment,
and 1.5, Rear Panel Equipment.

Shut down any host(s) to be connected to the LOCAL DWZGA unit.

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2–1

DWZGA User’s Guide

Figure 2–1 Typical Fiber-Optic UltraSCSI Extender Configuration

DW ZGA

S H R -1 0 03

2–2

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Chapter 2. Installation

Press 0 on the 0/1 power switch on the rear panel of the LOCAL DWZGA
unit.

If your power source is 115V ac, verify that the notch in the 115/230 voltage
selector slide switch is at the factory-set 115 position.

If the power cord supplied with the DWZGA is not compatible with the ac
wall outlet in your region, obtain a suitable power cord that meets the
following criteria:
•

Rated for use at the available ac voltage with a current rating of at least
125% of the current rating of the DWZGA; that is, 7.5 amperes at 100 to
120V ac, or 5 amperes at 200 to 240V ac.

•

The Ac plug must be terminated in a grounding-type male plug designed
for use in your region. The plug ends must be labeled or marked to
indicate they have been certified by an agency acceptable in your region.

•

The connector at the DWZGA end must be an IEC 320, sheet C13, female
connector (or equivalent EN 60 320 connector).

•

The cord must be less than 14.8 feet (4.5 meters) long and, for use in
Europe, be created with <HAR> (harmonized) or VDE certified cordage.

Connect the power cord to the rear of the LOCAL DWZGA unit as shown in
Figure 2–2, and connect the other end of the power cord to an ac source.

Connect the SCSI cable from the host to either of the SCSI connectors on the
rear panel of the LOCAL DWZGA unit.
NOTE
If your configuration has no SCSI targets on the
LOCAL DWZGA side of the fiber channel link,
omit the following step and put a terminator on the
remaining SCSI connector as shown in Figure 2-3.

Connect the SCSI cable from SCSI target Ids 0, 1, 4, and 5 to the remaining
SCSI connector on the rear panel of the LOCAL DWZGA unit.

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2–3

DWZGA User’s Guide

Figure 2–2 Cabling Typical Configuration

DW ZG A
-O PT IC

S H R -1 0 06

Figure 2–3 Cabling with Terminator on One SCSI Port

DW ZGA
-O P T IC

S HR -1 007

2–4

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Chapter 2. Installation

Remove the rubber plug from the rear of the LOCAL DWZGA unit and
insert the optical fiber duplex SC connector from the fiber channel link into
the mating connector on the LOCAL DWZGA unit. Align the connector
keyways to ensure the correct polarity.

Repeat steps 1 through 5 for the REMOTE DWZGA unit on the other side of
the fiber channel link.

10. Connect the SCSI cable from SCSI target Ids 2, 3, 8, and 9 to either of the
SCSI connectors on the rear panel of the REMOTE DWZGA unit.
11. Put a terminator on the remaining SCSI connector on the rear panel of the
REMOTE DWZGA unit.
12. Remove the rubber plug from the rear of the REMOTE DWZGA unit and
insert the optical fiber duplex SC connector from the fiber channel link into
the mating connector on the REMOTE DWZGA unit. Align the connector
keyways to ensure the correct polarity.

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2–5

3
Configuration
This chapter contains procedures for configuring the LOCAL and REMOTE DWZGA
units.

3.1

Setting Switches on LOCAL Unit
The procedure below specifies the switch settings needed to obtain the typical
configuration identified in section 2.3, Cabling. If necessary refer to sections 1.4,
Front Panel Equipment, and 1.5, Rear Panel Equipment for information on the
DWZGA unit controls and indicators.
1.

Press 1 on the 1/0 rocker-type power switch on the rear panel of the LOCAL
DWZGA unit. If the front panel POWER indicator lights, go directly to step
3; otherwise, continue with step 2.

Press the alternate action push-button switch on the front panel and verify
that the front panel POWER indicator lights. If not, refer to section 5,
Troubleshooting.

Check the TARGETS LED indicators 0 through 15 to ensure they are all out.
If one or more indicators are lit, use the switch setting tool to press the
TARGETS PUSH TO CLEAR switch associated with each lighted
TARGETS indicator until all are out.

Using the switch setting tool, press the TARGETS PUSH TO SET switch to
light indicators: 2, 3, 8, and 9.

If the TPWR indicator is out, press the associated PUSH TO SET switch to
light TPWR, enabling terminator power.

If the WIDE indicator is out, press the associated PUSH TO SET switch to
light WIDE, enabling wide (16 bit) data transfer. In unusual cases where
narrow (8 bit) data transfer is required, leave the WIDE indicator out to
enable narrow data transfer.

If the SYNC indicator is out, press the associated PUSH TO SET switch to
light SYNC, enabling synchronous data transfer. In unusual cases where
asynchronous data transfer is required, leave the SYNC indicator out to
enable asynchronous data transfer.

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3–1

DWZGA User’s Guide

If the UA/DISC indicator is lit, press the associated PUSH TO CLEAR
switch to put out UA/DISC, disabling DWZGA unit attention. In unusual
cases where you know unit attention must be enabled, press the associated
PUSH TO SET switch, if necessary, to turn on the UA/DISC indicator.

Verify that both TERMPOWER and DIFFERENTIAL indicators are lit.

10. Verify that both SINGLE-ENDED and DIFFSENSE indicators are out.
11. Press the alternate action push-button power switch on the front panel and
verify that the front panel POWER indicator goes out, de-energizing the
whole DWZGA unit.

3.2

3–2

Setting Switches on REMOTE Unit
1.

At the REMOTE unit, repeat steps 1 through 3 in section 3.1, Setting
Switches on LOCAL Unit, above.

Check the TARGETS LED indicators 0 through 15 to ensure they are all out.

If one or more indicators are lit, use the switch setting tool to press the
TARGETS PUSH TO CLEAR switch associated with each lighted indicator
until all are out.

If the TPWR indicator is out, press the associated PUSH TO SET switch to
light TPWR, enabling terminator power.

If the WIDE indicator is out, press the associated PUSH TO SET switch to
light WIDE, enabling wide (16 bit) data transfer.

If the SYNC indicator is out, press the associated PUSH TO SET switch to
light SYNC, enabling synchronous data transfer.

Verify that both TERMPOWER and DIFFERENTIAL indicators are lit.

Verify that both SINGLE-ENDED and DIFFSENSE indicators are out.

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Chapter 3. Configuration

10. Press the alternate action push-button power switch on the front panel and
verify that the front panel POWER indicator goes out, de-energizing the
whole DWZGA unit.

3.3

Startup
1.

Complete the cabling procedure in section 2.3, and the switch setting
procedures of sections 3.1 and 3.2.

Insert the firmware diskette shipped with each DWZGA unit into the 3.5inch floppy drive in the front panel of the LOCAL DWZGA unit.

Repeat step 2 for the REMOTE DWZGA unit.

Press the alternate-action push-button power switch on the front panel of the
LOCAL DWZGA unit and verify that the front panel POWER indicator
lights.

Press the alternate-action push-button power switch on the front panel of the
REMOTE DWZGA unit and verify that the front panel POWER indicator
lights.

Verify that within 60 seconds after turning on the last DWZGA unit, the
FIBER indicator lights and stays lit, signifying a successful startup.

If the FIBER indicator remains off for either or both DWZGA units, or the
FIBER indicator blinks in an endlessly repeating cycle, or an ERROR
indicator flashes rapidly for 15 seconds followed by the DWZGA unit(s)
performing a complete reset, or the DIFFSENSE indicator lights: refer to
Chapter 5, Troubleshooting.

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3–3

4
Maintenance
This chapter contains procedures for cleaning the end faces on the fiber-optic cable
connectors of the fiber-optic link and the fiber-optic port on each DWZGA unit.

4.1

Tools and Materials Required
Tools and materials required are:

4.2

•

3-inch by 3-inch lens paper or soft, lint free cotton cloth

•

91% pure isopropyl alcohol

•

Canned air

•

200X viewer (optional)

Fiber-Optic Cable Connectors
WARNING
To avoid personal injury, make sure the
equipment is de-energized when cleaning the
fiber-optic cable connectors.

De-energize the equipment.

Fold the lens paper or cloth in half.

Lightly dampen the lens paper or cloth with the alcohol. Don’t saturate the
paper or cloth.

Lay the dampened paper or cloth on a clean flat surface.

Take an additional dry piece of lens paper or cloth, fold it in half, and lay it
down adjacent to the piece in the last step.

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4–1

DWZGA User’s Guide

Grasp the fiber-optic cable connector by its locking mechanism and place its
end faces near the top of the alcohol dampened lens paper or cloth. The end
faces of the connector (Figure 4–1) should be squarely in contact with the
lens paper or cloth.

Figure 4–1 Cleaning Fiber-Optic Cable Connectors

Using the connector’s locking mechanism, apply a slight downward pressure
on the connector and simultaneously drag and rotate the connector along the
length of the lens paper or cloth.

Perform this operation two or three times, making sure not to cover the same
area of lens paper or cloth previously contacted.

While maintaining your grip on the connector, lift it up and move it over to
the dry lens paper or cloth adjacent to the alcohol dampened piece.

10. Repeat step 6 using the dry lens paper or cloth instead of the alcohol
dampened piece.
11. Repeat step 9 two or three times, making sure not to cover the same area of
lens paper or cloth previously contacted.

4–2

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Chapter 4. Maintenance

WARNING
The contents of the air duster can used in the
following step is under pressure. Do not puncture
the container and don’t store it near heat or an
open flame. Exposure to a temperature above 120
degrees F (49 degrees C) may cause bursting.

12. Blow the connector dry with the canned air to remove any lint.
13. Inspect the connector end faces using the 200X viewer. Check to ensure there
are no streaks or debris on the end faces.
WARNING
To avoid personal injury while cleaning the fiberoptic ports, make sure the equipment is deenergized as a first step in the following
procedures.

4.3

Fiber-Optic Port
When the fiber-optic port on the rear panel of a DWZGA unit (Figure 1–4) gets
contaminated, the port must be cleaned using one of the three techniques detailed
below; namely:
•

Air duster (canister),

•

In-House air supply, or

•

Isopropyl alcohol.
WARNING
The contents of the air duster can used in the
following procedure is under pressure. Do not
puncture the container and don’t store it near heat
or an open flame. Exposure to a temperature
above 120 degrees F (49 degrees C) may cause
bursting.

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4–3

DWZGA User’s Guide

4.3.1 Air Duster
1.

De-energize the equipment.

Hold the can upright.
NOTE
In the following step, do not tilt, invert, or shake
the can. Tilting or inverting will dispense the
contents as liquid instead of air.

Direct the nozzle or extension tube of the air duster toward the port opening.
Keep the tip of the nozzle or extension tube 2 to 3 inches from the port
opening.

Press the trigger to dispense the air. Use short, quick blasts.

Spray each opening three times.

4.3.2 Using In-House Air Supply
The in-house supply used for this procedure must be either:
•

Nitrogen, or

•

Fully filtered air, water free.

Proceed as follows:

4–4

De-energize the equipment.

Set the air pressure to 15 psi.

Direct the air gun nozzle towards the port opening. Keep a distance of 2 to 3
inches between the nozzle tip and the receptacle opening.

Repeat steps 4 and 5 in Section 4.3.1.

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Chapter 4. Maintenance

4.3.3 Using Isopropyl Alcohol
NOTE
Limit the use of this technique to a maximum of
three successive applications.

In an extreme case, where air spraying is not sufficient to clean the contaminants
away from inside the port, proceed as follows:
1.

De-energize the equipment.

With a syringe, or the equivalent, dispense isopropyl alcohol (IPA) inside the
module port.

Let the IPA stay for at least 10 seconds.

Blow dry the inside of the port. Use any of the air spray methods described
above.

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4–5

5
Troubleshooting
This chapter contains procedures for troubleshooting the fiber-optic UltraSCSI extender.

5.1

Equipment Required
No equipment is required except the front panel indicators, and one rear panel
indicator, on each of the two (LOCAL and REMOTE) DWZGA units.
If you wish to troubleshoot using the diagnostic diskette shipped with each
DWZGA unit, refer to the instructions in the Disaster Recovery Solutions
Getting Started Guide, fully identified under Associated Documents in the About
This Guide section of this document.

5.2

Procedure
Refer to Table 5–1. Identify in the Symptom column the entry that best describes
your problem. Then use the corresponding entries in the Probable Cause and
Remedy columns to correct the problem. All switches, indicators, and connectors
named in Table 5–1 are located on the front panel of the DWZGA unit unless
another location is specified.
NOTE
Do not remove the cover from a DWZGA unit,
doing so will void the warranty.

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5–1

DWZGA User’s Guide

Table 5–1 Troubleshooting Table

5–2

Symptom

Probable Cause

Remedy

POWER
indicator stays
off when pushbutton power
switch is
pressed.

0 position on rear
panel 1/0 power
switch is selected.

Select 1 position on 1/0 power switch. If
POWER indicator doesn’t light, press pushbutton power switch again.

DWZGA power
cord connects to
outlet with no
power because of
blown fuse or open
circuit breaker.

Replace fuse or reset circuit breaker and
check POWER indicator again.

Normal startup,
as described in
section 3.3,
Startup, does
not occur.
Instead, the
DIFFSENSE
indicator lights.

Single-Ended
device connected
to differential SCSI
bus

Replace single-ended device with device set
up for differential signaling.

Normal startup,
as described in
section 3.3,
Startup, does
not occur.
Instead, the
ERROR
indicator flashes
rapidly for 15
seconds,
followed by a
pause while the
DWZGA unit
resets, then the
ERROR
indicator flashes
again in a
repeating cycle.

The DWZGA unit
is defective.

Replace the DWZGA unit.

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Chapter 5. Troubleshooting

Table 5–1 Troubleshooting Table (Cont.)
Symptom

Probable Cause

Remedy

Data can’t be
transferred
between the
LOCAL HOST
and the
REMOTE
targets through
the DWZGA
units and the
fiber-optic link.
The equipment
has been started
as described in
section 3.3,
Startup.

The fiber-optic link
is open (defective),
or the connections
to it are dirty.

Use a telephone to coordinate with a person
at the REMOTE end of the fiber-optic link.
Check the red LEDs on the rear panel of both
the LOCAL and REMOTE DWZGA units. If the
LEDs are both lit, the fiber-optic link, and the
connections to it, are good. Consider another
probable cause.
If the red LEDs are other than both on (out or
blinking in any combination), shut down the
DWZGA units by pressing the front panel
power switch on both units. Clean the fiberoptic connectors and ports as described in
section 4, Maintenance. Reconnect the fiberoptic cables and power on the DWZGA units
again.
If the red LEDs are other than both on, the
fiber-optic link is probably defective*. Contact
the agency that owns or maintains the fiberoptic link and ask them to check it.

There’s a problem
with the switch
settings on one of
the DWZGA units.

Repeat the procedures in section 3,
Configuration, allowing for differences
between the typical configuration and the
configuration you require.
Check the WIDE indicator. In most cases, it
should be lit. If the indicator is out, narrow
data transfer is enabled.
Check the SYNC indicator. In most cases, it
should be lit to enable synchronous data
transfer. If the indicator is out, asynchronous
data transfer is enabled.
Check the UA/DISC indicator. In most
installations, it should be out.

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5–3

DWZGA User’s Guide

Table 5–1 Troubleshooting Table (Cont.)
Symptom

Probable Cause

Remedy

(Continued)

There’s a cabling
problem in the
installation, or one
of the SCSI
connectors or
terminators has
bent pins.

Repeat the procedure in section 2.3, Cabling,
allowing for differences between the typical
configuration and the configuration you require.
Remove each SCSI bus connector and
terminator to check it for bent pins. If any are
found, replace the cable or terminator with a
new one. When reconnecting, ensure that each
connector is evenly seated with the connector
screws securely tightened.

*If the rear panel red LED on either DWZGA unit is out, not blinking, there’s a
possibility that the fiber module in one of the DWZGA units, and not the fiberoptic link, is defective. If a fiber digital data interface (FDDI) duplex SC patch
cable is available, you can verify that the fiber-optic link is defective. Shut down
the DWZGA unit at either end of the fiber-optic link, disconnect it and take it to
the site where the other DWZGA unit is installed. With both units shut down and
the SCSI equipment disconnected, use the FDDI duplex SC patch cable to
connect the fiber-optic ports on the two DWZGA units together. Then power
both DWZGA units on. If one of the red LEDs is out, the fiber module on that
DWZGA unit is bad. Replace the DWZGA unit. If the red LEDs both light, the
fiber-optic link between the two sites is defective.

5–4

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A
Manufacturer's Declarations
This appendix contains the Radio Frequency Interference (RFI) declarations for the
StorageWorks Fiber-Optic UltraSCSI Extender.

NOTE
The following statements are applicable to the
StorageWorks Fiber-Optic UltraSCSI Extender.

USA
This equipment generates, uses, and may emit radio frequency energy. The
equipment has been type tested and found to comply with the limits for a Class A
digital device pursuant to Part 15 of FCC rules, which are designed to provide
reasonable protection against such radio frequency interference.
Operation of this equipment in a residential area may cause interference in which
case the user at his own expense will be required to take whatever measures may
be required to correct the interference.
Any modifications to this device — unless expressly approved by the
manufacturer —- can void the user’s authority to operate this equipment under
part 15 of the FCC rules.
Shielded interface cables are required.
Japan

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A–1

DWZGA User’s Guide

CAUTION!
This is a Class A product. In a domestic
environment this product may cause radio
interference in which case the user may be
required to take adequate measures

ACHTUNG!
Dieses ist ein Gerät der Funkstörgrenzwertklasse
A. In Wohnbereichen können bei Betrieb dieses
Gerätes Rundfunkstörungen auftreten, in welchen
Fällen
der
Benutzer
für
entsprechende
Gegenmaßnahmen verantwortlich ist.

ATTENTION!
Ceci est un produit de Classe A. Dans un
environnement domestique, ce produit risque de
créer des interférences radioélectriques, il
appartiendra alors à l'utilisateur de prendre les
mesures spécifiques appropriées.

A–2

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