PDP-11/73 boot issues

Aaron Jackson aaron at aaronsplace.co.uk
Tue Sep 21 16:30:23 CDT 2021

Pete Turnbull via cctalk writes:

> On 21/09/2021 20:34, Chris Zach via cctalk wrote:
>> Can an MXV11 be used in a 22 bit system? I thought it was an 18 bit
>> device?
> MXV11-B is 22-bit.  MXV11-A is 18-bit but supposedly can be used in a 
> 22-bit system if the RAM is disabled.

Yeah this is a 22 bit card. Josh sent me an xxdp image which I could
easily boot from my scsi2sd (thanks!).  Seems to be reporting an error
with the CPU unfortunately:

]] .R ZKDJ??
]] ERROR # =001166
]] ERROR PC =040662
]] 043632

This happens regardless of whether W9 is installed or not (supposedly
disables the LTC register on the CPU?)

I'll see if I can borrow another CPU card form a friend this
weekend. Unless anyone else has any ideas?  Another suggestion on IRC
was to disable the PSU LTC and enable the LTC on MXV11 but will need to
look up some details on how to do this.


More information about the cctalk mailing list