DEC RK07 drive interface specs wanted

From: Paul Koning <pkoning_at_equallogic.com>
Date: Thu May 13 08:38:05 2004

>>>>> "Jochen" == Jochen Kunz <jkunz_at_unixag-kl.fh-kl.de> writes:

 Jochen> On Wed, 12 May 2004 23:30:49 +0100 Frank Arnold
 Jochen> <fm.arnold_at_gmx.net> wrote:

>> A solid state disc would be a great solution, however, wouldn't it
>> be a better (more general) aproach to work right off the unibus?
>> That would help anyone that -like me- has a unibus-cpu with
>> nothing else attached to it.
 Jochen> Sure. But who will fab the big, odd-shaped UniBus boards? Do
 Jochen> you have enough UniBus transceiver chips in stock?

Transceiver chips might be an issue. The board doesn't have to be all
that big -- quad size is enough.

>> If you have (?) the scematics of the RK611, how much work would it
>> be to put this into a fpga-design and add connect this to a
>> (better four) CF-card socket(s) Then a cheap 32mb CF card would
>> become a RK07+ media...
 Jochen> Hmmm. Replicating the RK611 in an FPGA is an interresting
 Jochen> idea. - If you can get complete shematics and there are no
 Jochen> funky things like an AMD bit slice CPU in it.

All the disk controllers before the MSCP family are hardwired logic
(except maybe the RL01, I'm not sure about that one -- and ignoring
screwball stuff like the Pro disk controllers). So none of them
should be all that hard.

If you want to emulate an old disk controller, the RH11 family might
be better, since those are larger disks, so you can put larger flash
cards to good use.

>> If you follow the RK611-design, there is no bothering about driver
>> issues,
 Jochen> There isn't one if I use the original RK611 controler. That
 Jochen> is an other issue: If you emulate the entire controler, you
 Jochen> have to make the emulation good enough for all operating
 Jochen> systems. It may work for a RK611, but what about a UDA50 with
 Jochen> its AMD bit slice CPU or a controler that has a T11 with some
 Jochen> non-trivial firmware on it. You can't stick this in a (cheap,
 Jochen> small) FPGA.

The UDA doesn't have a T11 in it. What it has is about 200 words of
microcode that implement a small instruction set that looks a lot like
a stripped-down simplified PDP11 instruction set. But it isn't a
PDP11 instruction set and it isn't done with a PDP11.

The 2901/2910 is a pretty simple beast; it would be easy enough to put
that in an FPGA, I'd think. The real issue is that you'd have a hard
time finding the UDA firmware.

Then again, if you wanted to emulate an MSCP controller, you don't
need to emulate the structure of the controller, you only need to
emulate the command interface. That is certainly doable. (It's been
done before -- consider the various PDP11 emulators.)

     paul
Received on Thu May 13 2004 - 08:38:05 BST