Appendix I: Scsi Installation And Lan Information; Introduction; Support For Older Scsi Devices; Setting Up Scsi Devices - TYAN THUNDER K7 User Manual

Appendix I: SCSI Installation and LAN Information

Introduction

The Adaptec 7899W enables you to connect up to 30 SCSI devices—such as very large arrays of high-
performance HDDs, external storage subsystems, clustered configurations, Ultra160 hard disk drives,
scanners, and CD-ROM drives.
The Adaptec 7899W can support up to two independent SCSI channels, each with a maximum through-
put of 160 MBytes/sec. SCSI Channel A (marked* either as "CH 1" or "CH A" on the board) has one inter-
nal connector. SCSI Channel B (marked* either as "CH 2" or "CH B" on the board) has one internal
connector.
You can connect Ultra160 and Ultra2 SCSI devices to the 68-pin Low Voltage Differential/Single-Ended
(LVD/SE) connectors on both SCSI channels. Or you can operate the newer Ultra160 and Ultra2 devices
at their maximum speed on Channel B while at the same time using legacy SCSI devices on Channel A.
This installation guide explains how to
• Set up SCSI devices
• Connect SCSI devices

Support for Older SCSI Devices

We recommend that if you have single-ended Ultra SCSI and earlier SCSI devices you connect them to
Channel A of the Adaptec 7899W SCSI and that you connect newer Ultra2 and Ultra160 SCSI devices to
Channel B. This allows the Adaptec 7899W to support newer Ultra160 and Ultra2 SCSI devices at speeds
up to 160 MBytes/sec while at the same time supporting Ultra (legacy) devices at speeds up to 40
MBytes/sec. It also allows you to use longer cable lengths for the newer SCSI devices.
If you connect Wide Ultra/Ultra SCSI devices to the same SCSI channel as
Ultra160 and Ultra2 SCSI devices, the data transfer rate for the Ultra160 and
NOTE: Ultra2 SCSI devices will drop to Ultra SCSI performance levels. To achieve maxi-
mum data transfer rates for the newer SCSI devices, be sure to connect them on
their own SCSI channel.

Setting up SCSI devices

There are several things you may need to do to your SCSI devices before you connect them to the
Adaptec 7899W SCSI:
• Check the SCSI IDs
• Set the termination
• Connect the power cables
* subject to change without notice
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