Installation manual

13 ATTO Technology Inc. ATTO Utilities Installation and Operation Manual
1.3 ExpressPCI NVRAM Settings
The settings in the NVRAM tab vary depending upon the selected storage controller and the operating system.
ATTO storage controllers are designed to operate
properly using factory settings. Entering invalid or
incorrect settings when using an NVRAM
configuration utility such as the ATTO ConfigTool may
cause your storage controller to function incorrectly.
CAUTIONCAUTION
Back up system data when installing or
changing hardware configurations.
Use caution when making changes to NVRAM
settings and only make changes to those with which
you are familiar. Once you have made the desired
changes, click
Commit to save the changes.
Changes do not take effect until you reboot the
system.
If you do not want to make any changes, you may
choose one of the following
• Defaults: restores the storage controller to
factory default settings. The Commit button
must be clicked to save any changes.
• Restore: reverts to the NVRAM settings saved
the last time the Commit button was used.
Clicking Commit is not necessary.
The upper part of the NVRAM Config panel contains
common NVRAM settings which pertain to the entire
channel. The lower part contains settings which can be
set for each SCSI ID on the channel.
Controller ID
Choices: 0-15
Default: 7
The ExpressPCI SCSI storage controller is normally set
to SCSI ID 7 because ID 7 has the highest priority on the
bus. The setting should remain at ID 7 unless you are
instructed to change it by an ATTO Technical Support
representative.
Termination
Choices: Auto, High
Default: Auto
Set to Automatic unless there is a narrow SCSI cable
connected to either the internal or external connector.
Selection Timeout (ms)
Choices: 1ms - 1 sec.
Default: 250 ms
Specifies the amount of time a device has to respond to
being selected. The time value can be lowered to speed
up the boot process. If the value is lower than the
recommended 250 ms, some devices may not have
enough time to respond.
Fallback Sync Rate (MB/sec.)
Choices: 40/20, 20/10 and 10/5
Default: 40/20
Specifies the maximum synchronous transfer rate to be
negotiated when the storage controller detects a Single-
Ended SCSI bus. The bus is Single-Ended when
UltraSCSI devices are connected to the bus.
Bus Reset Delay (sec.)
Read only; no choices
Default: 3
Sets the time delay between the reset of the SCSI bus
and the scanning of the SCSI bus. This is a read only
parameter.
Quick Arbitrate & Select
Choices: disabled, enabled
Default: enabled
If enabled, improves performance by reducing the time
required to gain control of the SCSI bus. QAS can only be
enabled if all target settings are set to
Sync DT-IU and
all devices on the bus support QAS.
Wide IDs
Choices: enabled (targets 0-15), disabled (targets 0-7)
Default: enabled
This setting is available only in Mac OS X and for Ultra160
or Ultra/WIDE ExpressPCI storage controllers.
Boot Driver
Choices: enabled, scan only, disabled
Default: enabled
If enabled and disk drives or a bootable CD are detected
during the bus scan, the BIOS driver remains resident. If
disabled, the BIOS starts, resets the storage controller
chip and unloads the driver.
If
Scan Only is selected, the BIOS driver scans the bus
and displays the devices attached, then unloads itself
after a brief delay.