Subject: Re: Why a pdp-11 (fwd)

From: [email-masked] (Robert Smith)
Date: Tue, 27 Dec 1994 12:42:44 -0500 (EST)

JL said: 
> On Thu, 22 Dec 1994 [email-masked] wrote:
> 
> > Field Circus told me the same story about never turning the drive off, which
> No!  All of them are single-sided.  The DS is just the arbitrary notation 
> - DS32 - as opposed to DF32.  It's DEC's way of specifying an expander 
> disk.  The RF gets RS expanders, etc.

CJL et al: DF and DS are not arbitrary designations.  Dick Best, as Chief 
Engineer, assigned nomenclature and model numbers.
DF equates to Disk, Fixed.
DS equates to Disk, Slave.
RK equates to Disk, Kartridge.
RF started being used (along with RP/RS/etc) when the D was assigned to
Datacomm devices (DP8e, DP11, DH11, DM11, DMC11, DHL8, etc
The meanings have changed over the years but that was how it was when the
alpha vice numeric designations were started.
Bob

---

From: "Michael A. Patton" <[email-masked]>
Date: Tue, 27 Dec 1994 22:20:55 EST

From: Robert Smith <[email-masked]>
   Date: Tue, 27 Dec 1994 12:42:44 -0500 (EST)

   Datacomm devices

And the story, as I heard it, was that "R" was chosen for "Rotating"
which makes:
   RK equates to Disk, Kartridge.
really RK => Rotating Kartridge and the expansion of RF (Rotating,
Fixed) sound like an oxymoron (it's "Rotating media, Fixed heads").

	-MAP