[Info-vax] OT: obscure PDP11 OSes (even more dinosaury)

[Jan-Erik Soderholm]

David Froble skrev den 2015-06-22 17:29:
> Johnny Billquist wrote:
>> On 2015-06-15 15:36, Simon Clubley wrote:
>>> On 2015-06-15, Dirk Munk <munk at home.nl> wrote:
>>>> bill at server3.cs.uofs.edu (Bill Gunshannon) wrote:
>>>>>
>>>>> Of course, all of this still doesn't explain how the VAX was
>>>>> "a best-seller" when compared to the PDP-11 when the PDP-11
>>>>> sold 50% more systems.
>>>>>
>>>>
>>>> Because one VAX could do the work of several PDP-11's?
>>>
>>> In the early days of the VAX, wasn't there some literature floating
>>> around showing how the PDP-11 was faster at some things than the VAX ?
>>>
>>> This was before my time however so I may be wrongly remembering
>>> something I read in the past.
>>
>> Interrupt response times on the PDP-11 are way better than on VAXen,
>> which led to people not wanting to downgrade from a PDP-11 to a VAX...
>>
>>     Johnny
>>
>
> Swapping can be rather detrimental to observed interrupt times ....
>
> When your program is sitting in memory, because it can, things are usually
> better.
>
> Ok, I'm not saying there weren't some things the PDP-11 did better, when it
> wasn't over burdened with more tasks than the memory could handle.

Many former PDP-11 applications (where "real-time" and interrupt respons
time matters) have probably been replaced with PLC based or similar
"embedded" solutions.

The VMS system can then talk directly to the PLCs (or other boxes)
instead...