RKV11D vs RK11D (was Re: Anyone Care About RT-11)

From: Jerome H. Fine <jhfinepw4z_at_compsys.to>
Date: Sun Apr 28 21:58:24 2002

>Ethan Dicks wrote:

> --- Carl Lowenstein <cdl_at_proxima.ucsd.edu> wrote:
> > > From: Ethan Dicks <erd_6502_at_yahoo.com>
> > > I have an RKV11D...
> I also happen to have an RK11C, but in 18 years, I have never managed
> to hook it up and power it on. Got the prints, got spares, got drives,
> etc. Don't got enough time. :-(

Jerome Fine replies:

I have an RK05 drive - probably working, but no Qbus controller. I also
don't have enough time, but before I have to weed the patch of old
PDP-11 Qbus systems (I don't have any Unibus systems since they
are just too heavy), I want to transfer a number of old RT-11 distributions
to a hard disk drive and then to a CD.

> > The RKV11D is really an RK11D with a different bus interface.
> > Sort of a built-in Qniverter.
> That makes sense. The handle numbers on the boards in the controller
> enclosure match the RK11D, so I figured that was what was going on.

So DEC actually made a Qbus compatible controller for the RK05?

> Looks like a 16-bit bus extender paddle card for the Qbus end, plus
> a strange bus interface in the controller box.

That long ago, DEC did many strange things.

> > Unfortunately the designers skimped on the extended address bits,
> > so the RKV11 is 16-bit address space.
> Not surprising. That seriously limits what I can do with it.

If necessary, you could add a bounce buffer to the device driver
to take care of the problem. I did this with the DYX.SYS
driver - worked very well.

> I may try to resurrect the 11/03 that this RKV11D came with, but I'd
> be limited in what I could do with RT-11 at that point. Will Kermit-11
> work for me if I only have 56KB of RAM? Is it possible to run a KDF11
> CPU in a 16-bit-address environment? All I really want to do is make
> physical backups of disk packs, etc., and get them to a CD burner.

It is also possible to run a KDJ11 system with just 56 KBytes of RAM!
And with the KDJ11, it is usually possible (normally there are actually
64 KBytes of RAM, but the IOPAGE takes away 8 KBytes) if you have
the correct memory boards (like the M8044s) to reduce the IOPAGE
to 4 KBytes and then have 60 KBytes of memory.

As for running with RT11FB (or even RT11SJ which slows things down
too much), RT-11 will run Kermit very well in a 56 KByte memory
space. If you can copy the files to a SCSI hard drive, then the second
stage is a CD.

> > I think that hardware hacks to add two address bits to make the RKV11
> > compatible with the RK!1 have been published, but I don't remember where.
> Ooh! I'd love to see it. I _do_ have some 22-bit bus extender cards/
> cables (from a dual BA23 uVAX system)... so if the BC08 cables are
> wired the same, I might be able to forego modding the Qbus end.

Any idea where that might be.

I don't know if this request is reasonable, but anyone who can loan me
a Qbus RK05 controller can have the RK05 drive after I copy the
RK05 files to a SCSI hard drive. They can have the RK05 packs
as well.

Anyone want to consider this - or else just a loan of the Qbus controller?
I have a number of old RT-11 distributions that I want to copy to a CD
and make available to RT-11 hobby users. Since they are all prior to
V5.03 of RT-11, they can be made available under the same terms
as the present V5.03 distribution of RT-11.

Sincerely yours,

Jerome Fine
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Received on Sun Apr 28 2002 - 21:58:24 BST

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