Dell Dimension 2200, Руководство пользователя

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Installing and Configuring SCSI Drivers 3-3
SCSI Device Settings
The SCSI device settings allow you to configure certain
parameters for each device on the SCSI bus. To configure
a specific device, you must know the SCSI ID assigned to
that device. If you are not sure of the SCSI ID, see
“Using the SCSI Disk Utilities” found later in this
section.
•
Initiate Sync Negotiation. This option determines
whether the host adapter initiates synchronous data
transfer negotiation (sync negotiation) between itself
and the device. The default setting is Yes.
The host adapter always responds to sync negotia-
tion if the SCSI device initiates it. If neither the host
adapter nor the SCSI device initiates sync negotia-
tion, data is transferred asynchronously.
Normally, you should leave the Initiate Sync Negoti-
ation setting enabled, because most SCSI devices
support sync negotiation and because it allows for
faster data transfer.
NOTE: Some older SCSI-1 devices do not support
sync negotiation. This may cause your computer to
operate erratically or hang if Initiate Sync Negotia-
tion is set to Yes. Set Initiate Sync Negotiation to No
for these devices.
•
Maximum Sync Transfer Rate. This option sets the
maximum synchronous data transfer rate that the
host adapter supports. The host adapter supports
rates up to the maximum of 40 megabytes per second
(MB/sec). The default setting is 40 MB/sec (the
maximum).
If the host adapter is set to not negotiate for synchro-
nous data transfer, the maximum synchronous
transfer rate is the maximum rate that the host
adapter accepts from the device during negotiation.
(This is standard SCSI protocol.)
•
Enable Disconnection. This option (sometimes
called disconnect/reconnect) determines whether the
host adapter allows the SCSI device to disconnect
from the SCSI bus. Enabling disconnection allows
the host adapter to perform other operations on the
SCSI bus while the SCSI device is temporarily dis-
connected. The default setting is Yes.
Leave Enable Disconnection set to Yes if two or
more SCSI devices are connected to the host adapter.
This optimizes SCSI bus performance. If only one
SCSI device is connected to the host adapter, set
Enable Disconnection to No to achieve slightly bet-
ter performance.
•
Initiate Wide Negotiation. This option determines
whether the host adapter attempts 16-bit data transfer
instead of 8-bit data transfer. The default setting is
Yes.
NOTE: Some 8-bit SCSI devices may have trouble
handling wide negotiation, which may result in
erratic behavior or a hang condition. For these
devices, set Initiate Wide Negotiation to No.
When this option is set to Yes, the host adapter
attempts 16-bit transfer. When this option is set to
No, 8-bit data transfer is used unless the SCSI device
itself requests wide negotiation. The effective trans-
fer rate is doubled when 16-bit data transfer is used
because the data path for wide SCSI is twice the size
of normal 8-bit SCSI.
•
Send Start Unit Command. This option determines
whether the start unit command is sent to the SCSI
device at boot. The default setting is Yes.
Setting this option to Yes reduces the load on your
computer’s power supply by allowing the host
adapter to start SCSI devices one at a time when you
boot your computer. When this option is set to No,
the devices are allowed to start at the same time.
Most devices require you to set a jumper before they
can respond to this command.
NOTE: For many devices, if Send Start Unit Com-
mand is set to Yes, the boot time will vary depending
on how long it takes each drive to start.
Advanced Host Adapter Settings
The advanced host adapter settings should not be
changed unless absolutely necessary. Dell sets these val-
ues and changing them may cause conflicts with the
SCSI devices.
•
Host Adapter BIOS. This option enables or disables
the host adapter BIOS. The default setting is
Enabled.
NOTE: Several SCSISelect options are not valid
unless the host adapter BIOS is enabled.
If you are booting from a SCSI hard-disk drive con-
nected to the host adapter, the BIOS must be enabled.