RT-11 DY install

[Bill Gunshannon]

On 10/17/2018 07:19 PM, Jerry Weiss via cctalk wrote:
> On 10/17/18 1:53 PM, Don Stalkowski via cctalk wrote:
>> I'm trying to use a simulated RX02 disk (under simh) with RT-11
>> and can't seem to get the DY driver to install.
>>
>> Here's the relevant log:
>>
>> sim> set ry enabled
>> sim> att ry0 ry0.dsk
>> RY: creating new file
>> RY: buffering file in memory
>> sim> c
>>
>>
>> .install dy
>> ?KMON-F-Invalid device installation DL0:DY.SYS
>>
>> .dir dy.sys
>>
>> DY    .SYS     4P 20-Dec-85
>>   1 Files, 4 Blocks
>>   14841 Free blocks
>>
>> I've tried with 2 different software "kits", the one from the simh site
>> and the one from bitsavers.
>>
>> Any ideas?
>>
>> Thanks, Don
>>
>
> Try
> set cpu 256K
> set rx disable
> set ry enable
>
> show ry
> RY    address=17777170-17777173, vector=264, BR5, 2 units
>   RY0    512KB, not attached, write enabled
>     double density
>   RY1    512KB, not attached, write enabled
>     double density
>
> Note: Apparently the RY emulation won't load if more than 256K memory 
> is specified as the DEC hardware did not support DMA in a 22bit box.   
> I'm entirely not sure why SIMH has to enforce this as its possible to 
> work around (e.g. TSX+ supports buffering the IO). Anyone know how to 
> override and load in SIMH?

If it didn't it wouldn't be emulating real PDP-11 hardware.  I have a
number of RX02 systems and they do  not work with more than
256K.

bill