DEC KM11 (Was: DEC KL11)

Paul Birkel pbirkel at
Fri Sep 24 04:11:07 CDT 2021

> -----Original Message-----
> From: cctalk [mailto:cctalk-bounces at] On Behalf Of Tony Duell via cctalk
> Sent: Friday, September 24, 2021 4:12 AM
> To: Noel Chiappa; General Discussion: On-Topic and Off-Topic Posts
> Subject: Re: DEC KM11 (Was: DEC KL11)
> On Thu, Sep 23, 2021 at 6:38 PM Noel Chiappa via cctalk
> <cctalk at> wrote:
> > Huh? The KM11 doesn't plug into the UNIBUS (or QBUS); it's a MASSBUS device (a
> > solid-state storage device, actually), so it plugs into an RH11 or RH70 or
> > something like that. (I should work with the VAX MASSBUS controller, too.)
> > So the question 'is it 18 bit compatible' makes no sense.
> Were there 2 things called the KM11?
> The KM11 that I know is the maintenance unit, composed of a W130 and
> W131 plugged together. It goes into a specially-wired connector on
> some older PDP11s (e.g. the 11/45), controllers (e.g. RK11C) and
> periperals (e.g. RX01).
>  I have a pair of real DEC ones, and a clone I built to do tests on my
> PDP11/45 before I got the DEC ones.
> -tony

I think that we're all talking about the ML11-A, or at least are intending to ... although the Subject line has been erroneous from the get-go ...

As Mark said:

EK-0ML11-TD *ML11 Technical Description
EK-0ML11-TM *ML11 Technical Manual
EK-0ML11-UG *ML11 User's Guide


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