Resurrecting RK05

Paul Anderson useddec at
Wed Jan 7 14:11:28 CST 2015

I nave 2 RK11-C backplanes, a Diablo drive, and a Plessey controller here
if anyone is interested. Feel free to make me an offer off list.

On Wed, Jan 7, 2015 at 11:44 AM, tony duell <ard at> wrote:

> >
> > The standard RK8E do a select using just one pin, meaning you can have
> > at most 4 drives on the system.
> > The RK11 have a binary unit number encoding, meaning you can have 8
> drives.
> The RK11-D (and I guess RKV11) use binary encoding on the select lines, so
> up to
> 8 drives on the cable. The RK11-C uses 1-of-n encoding (like the RK8E) and
> allows
> for 4 drives per cable. But the RK11-C has 2 cable connectors, so you can
> have
> 8 drives on it.
> The older RK02 and RK03 drives (Diablo model 30) used 1-of-n encoding only,
> and will not directly work with the RK11-D. I seem to remember a Plessey
> clone
> of the RK11-D which had an interface board in the disk cable slot which
> had a
> decoder IC on it to allow for 1-of-n selects.
> > More fun is that the same pins were used for both binary and 1ofN
> > selection. I don't remember how on earth this was detected/handled by
> > the drives, as I don't remember anything beyond the unit setting rotary
> > switch on one of the boards of the RK05.
> There was a pin on the drive interface connector which if high enabled
> 1-of-n
> selects (it was normally pulled high by the terminator). If pulled low
> (done
> by an RK11-D controller) the drive used binary selects.
> -tony

More information about the cctalk mailing list