Dell PowerEdge 6400 User Manual
Page 60
Boot Device Options
The boot device options allow you to specify the device from which to boot your computer:
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Boot Channel
— Specifies the boot channel (A or B) for the dual channel Adaptec AIC-7899 host adapter. The default is A First.
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Boot SCSI ID
— Specifies the SCSI ID of the device from which you want to boot your system. SCSI IDs are set for the hard-disk drive
according to the drive's location on the backplane board. The default for Boot Target ID is 0.
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Boot LUN Number
— Allows you to specify a particular logical unit number (LUN) from which to boot your boot device if your boot device
has multiple LUNs and Multiple LUN Support is enabled (see "
Advanced Host Adapter Settings
"). The default is 0.
SCSI Device Configuration Settings
The SCSI device configuration 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 "
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Initiate Sync Negotiation
— Determines whether the host adapter initiates synchronous data transfer negotiation (synchronous
negotiation) between itself and the device. The default is Yes.
Synchronous negotiation is a SCSI feature that allows the host adapter and its attached SCSI devices to transfer data in synchronous mode.
Synchronous data transfer is faster than asynchronous data transfer.
The host adapter always responds to synchronous negotiation if the SCSI device initiates it. If neither the host adapter nor the SCSI device
initiates synchronous negotiation, data is transferred asynchronously.
Normally, you should leave the Initiate Sync Negotiation setting enabled, because most SCSI devices support synchronous negotiation and
because it allows for faster data transfer.
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Sync Transfer Rate
— Sets the maximum synchronous data transfer rate that the host adapter supports.
The AIC-7899 host adapter supports rates up to 160 megabytes per second (MB/sec). The default for the AIC-7899 host adapter is 160
MB/sec.
The AIC-7880 host adapter supports rates up to 20 MB/sec in narrow SCSI mode as implemented on this system. The default for the AIC-
7880 host adapter is 20 MB/sec.
If the host adapter is set to not negotiate for synchronous 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.)
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Enable Disconnection (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 disconnected. The default 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 better
performance.
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Initiate Wide Negotiation
— Determines whether the host adapter attempts 16-bit data transfer instead of 8-bit data transfer. The default is
Yes.
When this option is set to Yes, the host adapter attempts 16-bit data transfer. When this option is set to No, 8-bit data transfer is used
unless the SCSI device itself requests wide negotiation. The effective transfer 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.
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Send Start Unit Command
— Determines whether the start unit command is sent to the SCSI device during the boot routine. The default 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.
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Enable Write Back Cache
— Signals the completion of a write request as soon as the data is in cache. Actual writing to the disk occurs at
a later time. The default setting is N/C.
NOTE: Some older SCSI devices do not support synchronous negotiation. This may cause your computer to operate erratically or hang
if Initiate Sync Negotiation is set to Yes. Set Initiate Sync Negotiation to No for these devices.
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.
NOTE: For many devices, if Send Start Unit Command is set to Yes, the boot routine time will vary depending on how long it
takes each drive to start.