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

[Craig A. Berry]

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.