[Info-vax] RB730 Integrated Disk Controller (R80/RL02) usable with VAX-11/750?

[John Wallace]

On May 2, 10:52 am, vaxorcist <vaxorc... at googlemail.com> wrote:
> Can the RB730 Integrated Disk Controller (primarily developed for R80/
> RL02 drives with the VAX-11/730 and /725) be used with the VAX-11/750?
> This might have been a "low cost" solution to connect disk drives to
> the /750.
>
> Any hints welcome!
>
> Regards,
>
> Ulli

I don't think it sits on the Unibus in the traditional way.

EK-RB730-TD is the VAX 11/730 IDC Technical Description and there's
one at
http://www.bitsavers.org/pdf/dec/vax/730/EK-RB730-TD-001_VAX-11_730_IDC_Technical_Description_Sep82.pdf

Figure 2-1 shows the interfaces. Yes there are many UNIBUS signals.
But there are also signals which I would not expect on the UNIBUS, but
which are associated with the RB730's tight integration with the
VAX730 CPU e.g. CPU Writable Control Store stuff. Why is that there?
Not 100% sure, but I think the AMD2900 bitslice micro which is the
heart of the VAX 730 CPU also plays an essential part in the operation
of the RB730. Given that, I wouldn't expect it to work (let alone be
supported) on a 750. But I could be wrong.

I'm afraid I don't have any suggestions for "low cost" storage
adapters for a 750, maybe others do?