[Info-vax] What does VMS get used for, these days?

[Dave Froble]

On 11/6/2022 6:42 PM, Craig A. Berry wrote:
>
> On 11/6/22 12:58 PM, Arne Vajhøj wrote:
>> On 11/6/2022 8:55 AM, Scott Dorsey wrote:
>>> First thing: VMS has heavyweight processes.  There's a lot of stuff in the
>>> process, so spawning off new processes takes a good while, and you don't do
>>> it very often.  Conceptually different than Unix and Unixalikes where the
>>> processes are lightweight and the overhead of a fork is minimal so you fork
>>> off a new process for nearly everything.
>>
>> That was the gospel for many years.
>>
>> But the overhead of creating a process much be a lot less
>> significant on an Itanium or x86-64 today than it was on
>> a VAX 35 years ago.
>>
>> And I believe that for true high performance then even
>> *nix are switching from traditional forking to threads.
>
> And not everyone thinks fork() is such a great idea anymore even aside
> from performance considerations, e.g.:
>
> https://www.microsoft.com/en-us/research/uploads/prod/2019/04/fork-hotos19.pdf
>
> This could be good news for VMS if major applications start using
> posix_spawn() instead of fork(); it would map much better to the VMS way
> of doing things, and it might even be reasonable to provide a
> posix_spawn() API on VMS.
>

I could argue that VMS already has several APIs for spawned and detached 
processes, but, I'd be the first to agree that the devil is in the details. 
I've used subprocesses and detached processes for a long time, and developed my 
methods for performing such tasks.

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David Froble                       Tel: 724-529-0450
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