CBI/CGI Technical Reference
Chassis PlansC-10
adapter to perform other operations on the SCSI bus while the SCSI device is tempo-
rarily disconnected.
When the Enable Disconnection option is set to the default setting of Yes , the SCSI
device may disconnect from the SCSI bus. The SCSI device may choose not to
disconnect, however, even if permitted by the adapter (this can usually be configured on
the SCSI device). When this option is set to No, the SCSI device cannot disconnect from
the SCSI bus.
Leave the Enable Disconnection option set to Yes if the adapter connects to two or more
SCSI devices. This optimizes SCSI bus performance. If the adapter connects to only
one SCSI device, set this option to No to achieve slightly better performance.
Available options are:
Yes
No
Initiate Wide Negotiation
This option, which only displays for 16-bit adapters, lets the adapter initiate wide negoti-
ation with a 16-bit SCSI device. The adapter will not attempt wide negotiation with 8-bit
devices, so you can leave this option set to Yes even if the bus incl udes 8-bit devices.
Available options are:
Yes
No
Send Start Unit Command
This setting determines whether the adapter sends the Start Unit command (SCSI
command 1B) to the SCSI device. The default setting for Send Start Unit Command is
No (disabled).
Enabling this option reduces the load on a computer's power supply by allowing the
adapter to turn on SCSI devices one by one when the computer boots; otherwise, all
SCSI devices turn on at the same time. Before you enable this option for a device, make
sure the AIC-7880 BIOS is enabled. Also, check the device documentation to make sure
the device supports the command. On most devices, you must also change a switch or
jumper setting on the device to enable the device to respond to the command.
If you enable Send Start Unit Command for more than one SCSI device, the adapter
first sends the Start Unit command to the boot device specified in the Boot Target ID
option of the Boot Device Configuration screen. When the boot device responds, Start
Unit commands are sent to the remaining devices, beginning with the device with the
lowest SCSI ID. The boot time varies depending on how long each drive takes to spin
up.