Scsi Guidelines For Optimizing Performance - Compaq AP500 - Professional - 128 MB RAM Reference Manual

When an external SCSI device is connected to the external SCSI
connector on the rear panel of the workstation, that device becomes the
end of the SCSI chain and must be terminated.
SCSI drives on the SCSI controller must be either internal or in an
external storage system, but not both.
SCSI Guidelines for Optimizing
Performance
To maintain Ultra speeds, do not install more than four SCSI devices
on a SCSI bus.
Do not mix Wide-Ultra and narrow SCSI devices on the same SCSI chain
or the same controller. For example, if you plan to connect SCSI devices
to both the internal and external Wide-Ultra SCSI connectors, do not
install Wide-Ultra SCSI devices to the external Wide-Ultra SCSI
connector and narrow SCSI devices to the internal Wide-Ultra SCSI
connector.
For additional information about optional SCSI devices, refer to the
documentation included with the device or contact your Compaq authorized
dealer, reseller, or service provider.
Compaq Professional Workstation AP500 Reference Guide
8-13