ISO: PDP-11/40 LTC and Stack Limit options

Jerry Weiss jsw at
Mon Nov 21 15:58:04 CST 2016

> On Nov 21, 2016, at 2:13 PM, william degnan <billdegnan at> wrote:
> On Mon, Nov 21, 2016 at 2:37 PM, Josh Dersch <derschjo at> wrote:
>> Hi all --
>> I'm finally turning my attention back to my 11/40 (which I started working
>> on 7 years ago and never quite got around to finishing -- I've learned a
>> lot since then and I'm hoping to be able to debug it properly now).
>> My ultimate goal is to run V6 or V7 UNIX on it -- I have the MMU but I'm
>> looking for an M787 (line-time clock) and M7237 (stack limit register) to
>> complete the set.  I have other DEC stuff for trade, drop me a line...
>> Thanks!
>> Josh
> Just curious, are you aware whether these two are required to boot a RL02
> disk or certain versions of RT-11?  I have been experiencing difficulties,
> I only have the m737 iinstalled in my system.
> Bill

RT11 will run w/o an LTC.  

TTBOMR the stack limit register is not need for Single Job and the
other RT11 OS variants.  However a  program could overwrite the vector area
and cause an ungraceful shutdown.      Make sure the jumpers on the KD11-A are set
correctly for this configuration.

Using an RL02 to boot RT11 should be okay as well. 

jsw at

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