Trying to get my RLV11 working

Noel Chiappa jnc at
Thu Oct 29 12:44:40 CDT 2015

    > From: Ben Sinclair

    > the bc80m cable .. which I believe is a ribbon type of connector with a
    > ground strap on one end, then a round cable to the berg connector for
    > the back of the RL02. I think it's the cable pictured here:

Yes, that's the cable. But there's no ribbon cable anywhere in it: the
individual wires from the round cable go directly to the Berg (aka Du Pont)
female connector, which plugs into the male Berg header on the board.

The other end does not have a Berg connector, it's some sort of wierd-ass
connector that I don't know the proper name for. (The RK0[67] also uses them,
and I think maybe the MASSBUS too?)

    > The RLV11 and RLV12 seem hard to find, at least on eBay

They come by occasionally. I can probably find an RLV12 for you if you
want/need one.

    > so fixing this one might be the way to go!

Fixing an RLV11 is not for hardware beginners. Think logic analyzer, at

    > From: Johnny Billquist

    > I would primarily expect 16 bits addresses to be used on a KDF-11, but
    > I could be wrong.

11/23 ODT addresses are always 18-bit (whether the MMU chip is installed or
not); I don't know if attempting to look at memory above 56KB works without
the MMU, though.

    > Early revisions only supported 18 bit addressing, but later models
    > supported 22 bit addressing. But how that is reflected in the micro-ODT
    > on a KDF-11 I don't know.

I already bitched about this! Although it supports Q22 _on the bus_, their
ODT only supports Q18. There's no way to fiddle with high memory, except
via program!

    > I don't even know if it's actually micro-ODT, or some more primitive
    > console mode on that CPU.

AFAIK, it's the same ODT as all the other QBUS -11's (03, 73, etc - although
the /03 has the 'L' bootloader command that none of the others do, along with
a couple of other odd minor ones like '@').


More information about the cctalk mailing list