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 >
