Fujitsu Siemens Computers D1419, Техническое руководство, Страница: 21 / 32

Features
A26361-D1419-Z120-1-7419
English - 13
SCSI Device Configuration
Sync Transfer Rate
Fast SCSI devices, including the U320-SCSI controller, are capable of transferring data to and from
the SCSI bus at speeds ranging up to 320 Mbyte/s at synchronous data transfer.
The configurable
maximum data transfer rate is
320 Mbyte/s. For this setting the options "Wide Negotiation",
"Packatized" and "Disconnection" must be activated (YES).
Packetized
When activating the packetized option for the U320 SCSI operation not only data but also SCSI
commands and messages in synchronous operation are transferred. These are transferred together
with data in packages. With this more bus
bandwidth for real data transmission
are available. This
option is only for the U320 operation.
QAS
By the QAS (Quick Arbitration and Select) option the packages are transferred on the SCSI bus
without a bus free phase between the packages. As a result a higher throughput on the SCSI bus is
achieved
. This option is only for the U320 operation.
Initiate wide negotiation
This option determines whether the SCSI controller attempts 16-bit data transfer (Wide negotiation)
instead of 8-bit data transfer. As a result two byte
are transferred simultaneously
via the SCSI bus
instead of one byte.
Enable disconnection
The default setting is Yes (enabled).
This permits SCSI devices to enable the SCSI bus during command execution.
A typical example of this is a tape device that has no need to access the SCSI bus during rewinding
and can be "disconnected" from the SCSI bus for this period.
You can disable the function (
No
) if you have only connected one SCSI device. In this case,
disabling disconnection improves performance slightly.
Send Start Unit Command
The default setting is Yes (enabled).
When this feature is enabled, the SCSI devices which support this function are not started by
switching on the server until they receive a "Start Unit" command from BIOS of the U320 SCSI
controller. (To do this the U320-SCSI controller BIOS must not be disabled).
This function is used to distribute the high starting currents of the SCSI devices over a specific
period and to release the power supply of your server.
BIOS Multiple LUN Support
This option determines whether booting from a SCSI device that has multiple LUNs (Logical Unit
Numbers) is supported. The default setting is
No (disabled).