11/04 latest

Rod Smallwood rodsmallwood52 at btinternet.com
Sun Jun 5 02:58:54 CDT 2016


     Well lots fun with the 11/94 project. In fact its become an 11/84 
and 11/94 project.

After following Sherlock Holmes advice "when you have eliminated 
everything else.Whats left however unlikely is the answer"   I 
discovered  the RX211 needed to be in CDEF and not ABCD.  Why did I not 
know that?  Well I can only put it down to the fact all of the UNIBUS 
options I ever worked with were hex modules.

Next fascinating fact. You can switch between being an 11/84 and an 
11/94.  Although one box has three Qbus slots and the other (11/84) has 
four.  If you put an 11/84 CPU  in slot 1 and a MSV11-J (PMI) in 2 or 3 
it does its startup tests and goes into the monitor screen.

If you try to boot the RX02 in 11/84 mode you get

(the drive does get accessed - there's a nice healthy clonk)

Trying DY0

Error 101

Unexpected trap to location 114

See troubleshooting   documentation

Updated PC 173260          PCR Page = 62       Program listing address = 

R0 = 000000            R1 = 177170         R2 = 042131 R3 = 000000

R4 = 024000            R5 = 000000          R6 = 172276 R7 = 001600

In 11/94  mode it stops at the same point but does not give the error 

Comments gentlemen please

Rod Smallwood

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