Ultrix device names

[David Betz]

I have a MicroVAX II that is able to boot into Ultrix 4.3 single user  
mode. If I type "mount" it says that /dev/ra0a is mounted on /. I  
assume that is my ESDI hard drive since the drives plugged into my  
SDC-RQD11-EC ESDI controller are the only ones plugged into my  
system. So, my question is, what would the second drive on that  
controller be called? Would it be /dev/ra0b or /dev/ra1a? In other  
words, what do the "0" and "a" parts of the device name mean? Is "0"  
the controller and "a" the device on that controller?

I also have a TD Systems Viking SCSI controller in the system with a  
CD-ROM drive attached. What device name would I use for that? I'd  
also like to know how to address that drive from the MVII boot prompt  
so that I can boot directly off of the CD-ROM.

Thanks,
David