Microvax II hardware not recognized

Paul Koning paulkoning at comcast.net
Thu Aug 18 08:29:07 CDT 2016

> On Aug 17, 2016, at 11:37 PM, Douglas Taylor <dj.taylor4 at comcast.net> wrote:
> I've brought up a MicroVax II and installed VMS 5.5-2 on a SCSI2SD disk and it is fun to work with.  (I also installed openvms 7.2 without much drama)
> The problem I am having is that is has a TK50 tape drive and controller, but it never has shown up in the device list.  I even swapped in a different controller.
> The DHV11 did show up initially but has now disappeared from the device list.  Did I do this by removing boards and putting them back in?
> A RQDX2 board was put back in at a secondary CSR address and that shows up (it is connected to an RX50 which shows up in the device list).
> Does Autogen recognize new hardware?

A lot of Unibus/Qbus devices have "floating CSRs" which means they don't have fixed address assignments.  Instead, the correct address is based on a set of rules, which puts devices in an ordered list and assigns addresses in sequence.  There are tools to help with that.  If you get the address wrong, the system will see the device as the wrong type, and either fail to talk to it, or not talk to it at all (if it's not something the OS supports).


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