ATTO Technology UL2D, UL25 Appendix C Scsi Device & Cabling Limitations, Maximum, Bus Length

Page 20

APPENDIX C: SCSI DEVICE & CABLING LIMITATIONS

Due to the electrical noise incurred with high-speed data transfer rates, SCSI has cabling and device limitations. Table C-1 explains the maximum number of devices you may use relative to your cable distance. For example, take the single-ended distance in an UltraSCSI environment (Cells 3 & 4 in the single-ended bus length column). Look at the corresponding cells in the maximum devices column to determine the maximum number of devices you may connect at the specific distance. In an UltraSCSI environment, using a single-ended bus length of 3 meters, you can only connect 4 devices. Using a single-ended bus length of 1.5 meters, you can connect up to 8 devices.

SCSI Type

Single-Ended

Differential

LVD

Maximum

 

Bus Length

 

 

Devices

 

 

 

 

 

Fast SCSI

3 Meters

25 Meters

12 Meters

8

 

 

 

 

 

Fast/WIDE SCSI

3 Meters

25 Meters

12 Meters

16

 

 

 

 

 

UltraSCSI

1.5 Meters

25 Meters

12 Meters

8

 

 

 

 

 

UltraSCSI

3 Meters

N/A

N/A

4

 

 

 

 

 

Ultra/WIDE SCSI

N/A

25 Meters

12 Meters

16

 

 

 

 

 

Ultra/WIDE SCSI

1.5 Meters

N/A

N/A

8

 

 

 

 

 

Ultra/WIDE SCSI

3 Meters

N/A

N/A

4

 

 

 

 

 

Ultra2 SCSI

N/A

N/A

12 Meters

8

 

 

 

 

 

Ultra2/WIDE

N/A

N/A

12 Meters

16

SCSI

 

 

 

 

 

 

 

 

 

Table C-1: UltraSCSI Cabling and Device Limitations

Table C-1 lists the maximum number of devices you may connect at specific cable distances using differential and single-ended SCSI in various SCSI environments. In an UltraSCSI workgroup environment with a 7-drive tower, you are limited to 1.5 meters between the host and tower (this distance includes the cabling in the tower). For example, if the 7-drive tower requires 1 meter of cabling to connect all of its drives, the distance from the tower to the host would be .5 meters. Adding an ATTO SCSI Sidekick to this configuration would increase the distance between the host and tower to 2 meters.

Ultra2 SCSI is less sensitive to SCSI bus noise and offers you the ability to connect a full load of devices up to 12 meters. Use table C-1 to assist you when attempting to configure your workgroup. If you have any questions or issues occur with your configuration, please call an ATTO technical support representative.

Page 16

ATTO Technology, Inc.

Page 19 Page 21
Image 20
Page 19 Page 21
Contents Atto Technology, Inc Page Table of Contents Page Unpacking What is Atto ExpressPCI?Welcome Atto ExpressPCI UL2S adapter Installation Requirements Plug and PlayScsi Manager 4.3 Compatible About This ManualGetting a Fast Start Atto ExpressPCI Quick Installation For MacintoshAtto ExpressPCI Quick Installation For PC Atto ExpressPCI Ultra2 User’s Manual Cable Types Cabling for the Atto ExpressPCI UL2S & UL2D Scsi AdaptersCabling and Termination External Connectors Termination Terminating the Single-Ended Atto ExpressPCI UL2S and UL2DHardware Installation Before Installing your Atto ExpressPCI Scsi AdapterPlan your Scsi device connections Set Scsi device terminationHardware Installation Troubleshooting Atto ExpressPCI UL2D Model Appendix a Radio & Television InterferenceDeclaration of Conformity Canadian StandardsAppendix B Specifications GeneralOperating Environments Environmental and Physical SpecificationsAdvanced Scsi Appendix C Scsi Device & Cabling Limitations Scsi Type Single-Ended DifferentialMaximum Bus LengthScsi Workgroup Solutions Scsi Host AdaptersScsi Expansion Units Scsi Conversion UnitsHOW to Contact Atto TECHNOLOGY, INC Atto Technology, Inc
Top Page Image Contents