I used DEC for years, from straight -8 and  the11/45 at OMSI west lab, to
Metheus BSD 4.1/4.2, Sys V and RT-11 to the 90's with microvax, Those were
the days when it actually felt like you helping humanity, making life
better. Not any more.

On Mon, Dec 22, 2025 at 7:43 AM Nadav Eiron via cctalk <
[email protected]> wrote:

> Nope. Those are different drives. Mine has 2 *physical* RK05 drive IDs
> for each platter. Look at (PDF) pages 12-13 in this file:
>
> http://www.bitsavers.org/pdf/plessey/peripheral/Plessey_Minicomputer_Add-Ons_and_Peripherals_ca_1975.pdf
> I believe you're describing the PM-DD/11B and I have the PM-DD/11C. I have
> them on a PDP-11/45, so OS/8 isn't part of the equation :)
>
> Nadav
>
> On Mon, Dec 22, 2025 at 12:48 AM Christian Corti via cctalk <
> [email protected]> wrote:
>
> > On Thu, 18 Dec 2025, Nadav Eiron wrote:
> > > I have such a drive connected to an 11/45. It's branded as Plessey. The
> > > drives are double density RK05 compatible (i.e., it's like an RK05F + a
> > > "removable RK05F" with a specially marked removable pack that looks
> >
> > We have a couple of those, all branded as Plessey, but they are Wangco
> > type F drives. They have one fixed and one removable platter.
> > It is like two RK05, not RK05F.
> >
> > > physically like an RK05 pack) and present as 4 RK05 drives to the
> > > controller - two on the fixed platter and two on the removable one.
> > Haven't
> >
> > This would be on the PDP-8 / RK8E where each platter is divided into two
> > parts because OS/8 can't handle as many blocks as one entire platter has.
> > This makes your 4 logical drives, but it is still only like two RK05
> > drives.
> >
> > Christian
> >
>

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