Appendix I: Scsi Installation And Lan Information; Introduction; Features Of The Lsi Symbios Scsi Bios; Legacy Support For Non-Ultra160 Scsi Devices - TYAN Thunder i860 S2603 User Manual

Appendix I: SCSI Installation* and LAN Information

Introduction

With the dual channel onboard Ultra160 LVD SCSI option*, you can connect up to 30 SCSI peripherals
such as hard drives, CD-ROMs, and tape drives. Please note that this guide only provides basic instruc-
tions on connecting SCSI devices to your motherboard. For more detailed SCSI installation instructions,
refer to your SCSI device documentation or to LSI Logic's website: http://www.lsilogic.com
Features* of the LSI Symbios SCSI BIOS
Configuration for up to 256 adapters - any 4 can be chosen for INT13
(bootrom) support
SPI-3 Parallel Protocol Request (PPR)
Basic Domain Validation

Legacy support for non-Ultra160 SCSI devices

The LVD signaling used for Ultra160 devices operates differently than single-ended signaling used on
Ultra, Fast, and Fast Wide SCSI devices. Ultra160 LVD SCSI devices are designed with multi-mode capa-
bility so that if a single-ended device is connected to the Ultra160 LVD SCSI bus, the Ultra160 devices
automatically switch to single-ended mode. When an Ultra160 LVD SCSI device operates in single-ended
mode it is subject to the cable distance limitations and signal noise problems of that interface. LSI recom-
mends that single-ended Ultra and earlier devices be kept on a separate channel than the Ultra160 LVD
SCSI devices. This will permit the Ultra160 devices to operate at full speed and cable distances.

Setting up internal SCSI peripherals

Its very important that SCSI peripherals be set up before installing them to the SCSI connector. The setup
for SCSI peripherals usually involves setting SCSI IDs, checking for termination, mounting the peripherals
inside the chassis, and then hooking up power to each peripheral. Since setup can vary from peripheral to
peripheral, always refer to the peripherals documentation for specific instructions. Below are some guide-
lines for setting SCSI IDs and termination on your peripherals.

Checking SCSI IDs

Both the motherboard SCSI connectors and each peripheral you connect need to have a unique ID, rang-
ing from 0 to 15. IDs do not have to be sequential, as long as each connector and each peripheral has a
different number for each channel. Each SCSI channel on the motherboard is preset to SCSI ID and
should not be changed. If you will be booting from a SCSI HDD, its best to set the disk's ID at 0 or 1. Most
SCSI HDDs come from the factory preset to ID 0. The IDs for internal peripherals are usually set with
jumpers; external peripherals are usually set with a switch on the back of the peripheral. Check your
peripheral's documentation for more details.

Terminating SCSI devices

To ensure reliable communication on the SCSI bus, the peripheral on the end of each cable, or the end of
the cable itself, must have a terminator installed (or enabled). The peripherals between the ends of each
cable must have the terminator removed (or disabled). Check your peripheral's documentation for more
details.

Connecting SCSI peripherals

A total of 30 SCSI peripherals can be connector to the onboard SCSI connectors (15 devices per channel/
connector). Before connecting peripherals, be sure to also review Setting up internal SCSI peripherals
above.

Connecting internal cables for Ultra160 LVD SCSI devices

When connecting internal Ultra160 LVD peripherals there are special SCSI cables necessary to sustain
the higher speeds of LVD signaling. If your cables are not marked, you can identify most Ultra160 LVD
SCSI cables as having twisted pairs of the flat ribbon cable in between the device connectors. These
cables will usually have a terminator built into the end of the cable.
48
http://www.tyan.com