Paired 68000 systems for fault tolerance - was Re: out-of-mainstream minis

[Toby Thain]

On 2015-07-03 11:13 PM, Jon Elson wrote:
> On 07/03/2015 09:11 PM, Toby Thain wrote:
>> On 2015-07-03 8:09 PM, Glen Slick wrote:
>>>
>>> Apollo is the classic example of using plain 68K (two).
>>>
>>
>> I always associate it with Tandem:
>> http://www.hpl.hp.com/techreports/tandem/TR-86.2.pdf
>>
> Not sure what you are referring to, here.  Tandem did not use 68K
> processors as the main CPU
> in any of their machines.  (There could, possibly, have been 68Ks in
> some of the peripherals.)

Yes, you are right. The report gives some examples of dual 68000's in 
Tandem's peripheral subsystems.

I likely was thinking of Stratus, because I remember reading this before:
http://pages.cs.wisc.edu/~david/papers/ibmsj1987_stratus.pdf

Also Sequioa, who also used two 68000's operating in lockstep, described 
in P.A. Bernstein's paper that is comprehensively paywalled :(

--Toby


> They had their own 16-bit mini architecture, loosely based on HP's stack
> oriented minis.
>
> Jon
>