Acer Altos 9100 Series User Manual page 85

When set to yes, the SCSI device may disconnect from the SCSI bus. The SCSI
device, however, may choose not to disconnect, even if permitted by the SCSI
controller (this can usually be configured on the SCSI device). When set to no, the
SCSI device is not allowed to disconnect from the SCSI bus. The default setting is
yes.
You should leave Enable Disconnection set to yes if two or more SCSI devices are
connected to the SCSI controller. This optimizes SCSI bus performance. If only one
SCSI device is connected to the SCSI controller, set Enable Disconnection to no to
achieve slightly better performance.
Initiate Wide Negotiation
This option allows communication between all devices (lower 8-bit or upper 8-bit)
on the wide (16-bit) SCSI bus. When set to yes, each device can connect on the bus.
When set to no (disabled), communication can only occur on the lower 8-bits of the
16-bit SCSI bus. The default setting is yes.
Send Start Unit Command
This option, which is supported by some SCSI devices, determines whether the
Start Unit Command (SCSI command 1B) is sent to the SCSI device (most devices
do not require this). Enabling this option reduces the load on your computer's
power supply by allowing the SCSI controller to power-up SCSI devices one-at-a-
time when you boot your computer. Otherwise, the devices all power-up at the
same time. Most devices require you to set a jumper before they can respond to
this command.
When set to yes, the Start Unit Command is sent to the SCSI device during bootup.
When set to no, each SCSI device powers-up in its normal fashion. The default
setting is no.
The Send Start Unit Command setting is valid
only if the host adapter BIOS is enabled.
Chapter 4 - SCSISelect Configuration Utility 4-13