Scsi Parity Checking; Host Adapter Scsi Termination; Individual Settings For Each Scsi Device; Initiate Sync Negotiation - Adaptec AHA-3980 User Manual

SCSI Parity Checking

SCSI parity checking is a procedure used to verify the accuracy of
data transfer on the SCSI bus. By default, parity checking is enabled
on all AHA-398x channels. Disable parity checking for a channel if
any SCSI device on the channel does not support SCSI parity. Most
currently available SCSI devices support SCSI parity. If you are not
sure whether a device supports SCSI parity, read the documentation
for the device.

Host Adapter SCSI Termination

The default termination setting for each channel is enabled (for a defini-
tion of termination, see Terminating the SCSI Bus on page 5-12). Dis-
able termination for Channel A if you attach SCSI devices to both the
internal and external connectors of Channel A. For more information
on channel termination, see Terminating Channel A on page 5-14 and
Terminating Channels B and C on page 5-13.

Individual Settings for Each SCSI Device

This section describes the settings that can be changed individu-
ally for each device on the SCSI channel. For instructions on
changing the device settings, see Changing the AHA-398x Settings on
page 13-7.

Initiate Sync Negotiation

Synchronous negotiation is a SCSI feature that allows the SCSI channel
and its attached SCSI devices to transfer data in synchronous mode,
which is faster than asynchronous data transfer.
The Initiate Sync Negotiation setting determines whether the chan-
nel initiates synchronous negotiation with the SCSI device. At the
default setting, yes, the channel initiates synchronous negotiation
with the SCSI device. If you change the setting to no, the channel
does not initiate synchronous negotiation; however, the channel
always responds to synchronous negotiation if the SCSI device ini-
tiates it. If neither the channel nor the SCSI device negotiates for syn-
chronous data transfers, data is transferred in asynchronous mode.
Normally, you should leave the default setting, because most SCSI
devices support synchronous negotiation and because synchronous
data transfer is faster.
AHA-3980/3980W/3985/3985W User's Guide
Stock Number: 510810-00, Rev. D
Print Spec Number: 493479-00
Current Date: 3/1/99
Configuring the Adapter with SCSISelect
Page: 13-3
ECN Date: 3/19/96
13-3