Check The Scsi Ids; Terminate The Ends; Connecting Scsi Devices; Connecting Internal Ultra160 And Ultra2 Devices - TYAN THUNDER K7 User Manual

Since setup can vary from device to device, always refer to the device's documentation for specific
instructions. Below are some guidelines for setting SCSI IDs and termination on your devices.

Check the SCSI IDs

The Adaptec 7899W and each device you connect to it must have a unique SCSI ID number ranging from
0 to 15 on each channel. No two devices on the same SCSI channel can have the same SCSI ID.
The Adaptec 7899W is preset to ID 7 for each channel and should not be changed. If you boot from a
SCSI hard disk, make sure the hard disk SCSI ID is set to 0. (Most SCSI hard disks are preset to SCSI ID
0 at the factory.) The SCSI IDs for internal devices are usually set with jumpers; SCSI IDs for external
devices are usually set with a switch on the back of the device.

Terminate the Ends

To ensure reliable communication on the SCSI bus, the device at the end of each cable, or the end of the
cable itself, must have a terminator installed (or enabled). Terminators must be removed, or termination
must be disabled, on devices between the ends of each cable.
When connecting Ultra160 or Ultra2 SCSI devices, the SCSI bus must be termi-
nated either on the end of the cable (with a permanent terminator) or with a sepa-
rate terminating connector. Ultra SCSI and earlier single-ended devices can
terminate the bus directly from the device. If you use an Ultra SCSI terminator on
NOTE:
an LVD Ultra160 and Ultra2 SCSI bus you will force the bus to Single-ended
mode, limiting the speed and cable distance. For this reason be sure that you
have the necessary Ultra160 or Ultra2 cable or terminator before installing the
Ultra160 SCSI devices.

Connecting SCSI Devices

You can connect a total of 30 SCSI devices to the Adaptec 7899W,with up to 15 devices on each SCSI
channel. Before connecting devices, be sure to review Setting up SCSI Devices on p. 47.

Connecting Internal Ultra160 and Ultra2 Devices

A special 68-pin internal LVD cable is needed to connect internal Ultra160 or Ultra2 SCSI devices. If your
cables are not marked, you can identify most LVD cables as having twisted pairs of the flat ribbon cable
between the device connectors. Some cables are laminated so that they lay flat. Internal LVD cables usu-
ally have a terminator built into the end of the cable.
The Adaptec 7899W has two separate Ultra160 SCSI channels, as shown on the board map on p. 11.
Each channel has an internal LVD/SE connector to which you can connect internal SCSI devices. Follow
these steps to connect your internal Ultra160 and Ultra2 devices:
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