Adaptec 2025ZCR Installation And User Manual page 78

SCSI Device Configuration Options
The SCSI device settings allow you to configure certain parameters
for each device on the SCSI channel. To configure settings for a
specific device, you must know the SCSI ID assigned to that device.
If you are not sure of the SCSI ID, see
page A-14.
To access the SCSI Device Configuration options, select SCSI
Configuration, then select Additional Options. The SCSI Device
Configuration options are described in the table below.
Note: For maximum performance, Adaptec recommends that
you retain the default settings.
SCSI Device Configuration Options
Option
Maximum
Transfer Rate
Enable
Disconnection
Initiate Wide
Negotiation
QAS
Packetized
1. Adaptec recommends that you not enable QAS if you are using an enclosure that
contains Ultra320 expander ICs.
Default Description
N/A Determines the maximum data transfer rate
that the SCSI channel supports. The maximum
effective data transfer rate is doubled when
Initiate Wide Negotiation
devices are attached.
has no effect with 8-bit devices.)
Yes Determines whether the SCSI channel allows
the SCSI device to disconnect from the SCSI
channel (sometimes called Disconnect/
Reconnect or Reselection).
Yes Determines whether the SCSI channel attempts
16-bit data transfer instead of 8-bit data transfer.
The effective data transfer rate is doubled when
16-bit data transfer is used.
1
No Determines whether QAS (Quick Arbitration
and Selection) is used to eliminate overhead
and speed up data transfers on the SCSI bus.
Yes Determines whether SCSI packetization
(encapsulation) is used to reduce overhead and
speed data transfer. The packetized SCSI
protocol provides a method for transferring
command and status information at the
maximum rate.
Adaptec RAID Configuration Utility (ARC)
Using the Disk Utilities on
is set to Yes and 16-bit
(Initiate Wide Negotiation
A-13