Massbus - was: Re: VAX 11/750

[Josh Dersch]

On Thu, Feb 25, 2021 at 12:27 PM Al Kossow via cctalk <cctalk at classiccmp.org>
wrote:

> On 2/25/21 10:43 AM, Chris Zach via cctalk wrote:
> > Oh this is fun stuff. Is there a specification write-up anywhere on the
> MASSBUS overall?
>
> there is some documentation on bitsavers
>
> the register descriptions were intentionally obfuscated to prevent cloning
> that was figured out to make SIMH work
>

Interesting... Is this obfuscation documented anywhere (beyond looking at
SIMH code?)  I was working on an RH11/RPxx emulation for the Unibone that
was partially working (and that I should really get back to...)

- Josh



>
> the CDC drive interface was also slightly modified for the same purpose
>