DEC RK07 drive interface specs wanted

From: Tom Uban <>
Date: Thu May 13 21:09:01 2004

At 09:15 PM 5/13/2004 -0400, you wrote:

> >>>>> "Ethan" == Ethan Dicks <> writes:
> Ethan> On Thu, May 13, 2004 at 10:34:22PM +0100, Tony Duell wrote:
> >> > The real question is: What is more time consuming? Rebuild the
> >> RK07 or > build a solid state RK07 replacement.
> >>
> >> It also depends on what you want to do. To me, a classic computer
> >> system is more than just the CPU. The peripherals are part of it
> >> as well. Running a PDP11 with flash memory mass storage is not
> >> the same as running one with a demountable hard disk.
> Ethan> While in principal I agree, in years gone by, I was unable to
> Ethan> do more than play-load 2BSD on a real 11/24 because my largest
> Ethan> Unibus disk (that wasn't on a UDA-50) was and still is RL02s
> Ethan> on an RL11. These days, I have bigger Unibus CPUs (11/44,
> Ethan> 11/70), but in terms of pre-MSCP disks, 10MB is still a limit
> Ethan> for me (fortunately, I can get around this with 2.11BSD on the
> Ethan> 11/44 or the 11/70, but 2.9BSD was it for non Split I&D
> Ethan> machines)
> Ethan> Even though I appreciate and admire the older disks, I'm
> Ethan> pretty much stuck with RK05 and RL01/2. I'd love a solution
> Ethan> that emulates _some_ DEC disk controller (to avoid burning
> Ethan> boot PROMs, writing drivers for every OS I'd want to play
> Ethan> with, etc.). In order, a good solution for me would work with
> Ethan> 2BSD, RT-11, RSX and RSTS... there's plenty of interfaces that
> Ethan> fit the bill.
>If you can find adequate documentation for MSCP -- which should be
>doable -- then an MSCP controller would make a lot of sense. It's
>more complex in a sense, but it's command packet oriented, so the CSR
>piece is trivial. That one you can definitely do with just a register
>file to provide a register window (plus a DMA, but that can actually
>just be controller software reaching through a memory window over the
>One clear advantage is that you can pretty much pick whatever device
>size you want, because drivers query the controller for the disk size
>and believe what they are told. With older devices, you're stuck with
>the particular device sizes that existed then.
>If not MSCP, the next obvious choice is RH11, because that gives you
>the widest choice of the biggest drives, and it doesn't seem
>significantly harder than any of the others.

I disagree about MSCP making more sense. If the controller is to be used
on older pre-MSCP operating systems, then MSCP will be useless.

Received on Thu May 13 2004 - 21:09:01 BST

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