[Info-vax] DEC AXP 3000 model 300X question

[H Vlems]

The system has an on-board SCSI controller and a Turbochannel SCSI
controller with two SCSI interfaces.
The SRM prompt only shows disks attached to the on-board controller.
The devices are listed as DKAnnn.
Once VMS runs, these disks are named DKC, while the Turbochannel
attached devices are visible and use PKA0 and PKB0.
1) is this normal behaviour (this being my first Turbochannel system)?
2) I there a way to boot from a Turbochannel attached SCSI disk?
3) Is there a performance difference between the on-board and
turbochannel SCSI bus?
The 3000 model 300's have a at handicapped Turbochannel bus, hence the
last question.
Hans