[Info-vax] CRTL and RMS vs SSIO

[Stephen Hoffman]

On 2021-10-07 21:03:53 +0000, Dave Froble said:

> On 10/7/2021 1:01 PM, Stephen Hoffman wrote:
>> On 2021-10-07 16:18:28 +0000, Dave Froble said:
>> 
>>> I'm aware of how useful something like SSIO would be.  I'm just 
>>> appalled by the design and implementation.  As mentioned, it seems 
>>> aimed at just a few current uses, and totally ignores how useful it 
>>> would be for many more future uses.  This is rather consistent with the 
>>> long time apathy with which VMS has been treated.  It's more a patch 
>>> than an enhancement.   This is what I lament.
>> 
>> Alas, there's no other outcome when upward-compatibility is an 
>> overarching goal for the platform.
> 
> Now I''m just a dumb polock, wandered down out of the woods.  But I 
> just don't see where upward compatibility has anything to do with 
> enhancements to the DLM.  If existing calls continue to work as before, 
> and only when an optional extra parameter would enable new 
> capabilities, then upward compatibility just cannot be an issue.  At 
> least for this.

I was building on the "long term apathy" and "more patch than 
enhancement" comments, with the increasing difficulties even making 
comparatively minor or isolated changes and updates.

Larger changes can be Really Difficult with ~40 years of accumunated 
dependencies around, assuming the developers and schedule and funding 
are all available. (q.v. Hyrum's Law.)

There are sections of OpenVMS that would best be ripped out and 
replaced, or refactored, or re-architected, but that can't happen or 
can't easily happen while staying compatible with existing apps.

DLM itself needs better abstractions as some of the more common tasks 
are just absurdly involved to program within the existing API. Tasks 
such as selecting a primary app server for a host or a cluster, for 
instance. This is less of an issue for experienced OpenVMS programmers 
and for those with access to examples (cost and schedule and budget and 
ongoing support discussions aside), but this sequence is not something 
at all obvious to less-experienced developers. And even with 
experienced developers, mistakes still happen. And within a wider view, 
this DLM primary support is building local process and job control 
support, which is an omission I've commended on before.


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