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

[Jan-Erik Soderholm]

David Froble skrev den 2015-06-16 16:49:
> Bill Gunshannon wrote:
>> In article <mlouja$7aj$2 at dont-email.me>,
>>     Simon Clubley <clubley at remove_me.eisner.decus.org-Earth.UFP> writes:
>>> On 2015-06-15, Dirk Munk <munk at home.nl> wrote:
>>>> The PDP-11 was a 16 bit architecture. Writing larger programs on a
>>>> PDP-11 always involved using overlay. I've spend many hours trying to
>>>> construct my Cobol programs in such a way that I could use memory
>>>> resident overlay. Otherwise it would become disk-resident overlay, and
>>>> that involved lots of extra disk IO as the name suggests. That would
>>>> make an application a lot slower. Using RMS in supervisor mode also was
>>>> a must to keep a somewhat fast application.
>>>>
>>> The TKB overlay functionality (and it's associated documentation) is
>>> something I have _very_ gladly left in the past and have almost
>>> successfully purged from my memory. :-)
>>>
>>
>> Having spent the least of my PDP-11 time on RSX I can't say how hard
>> it was to use TKB but I do overlays on Ultrix-11 and have never found
>> it particularly difficult.
>>
>> bill
>>
>
> It's not that it is so difficult, the real issue to me is that it dictates
> how you design and write code.  This then restricts your options.
>
> While I'll admit that such restrictions can have some beneficial side
> effects, they are still restrictions, and such is counter-productive.
>
> I had a rather old application that had a separate sub-program for just
> about every action.  Each prompt for input was a sub-program.  It was much
> more work.
>
> Now, I still have a fondness for modular coding, and for library(s) of
> support routines.  Just seems to me to be a better method.  Not sure how
> much of that came from a history with TKB.

I remember overlaying a Fortran application with both RMS and DTR-11
libraries. Quite complex overlay structure but reasonable well
documentered...

Jan-Erik.