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

[Arne Vajhøj]

On 11/7/2022 3:48 PM, Scott Dorsey wrote:
> =?UTF-8?Q?Arne_Vajh=c3=b8j?=  <arne at vajhoej.dk> 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.
> 
> Yes, but fork is faster on Unix than it used to be also.

Of course.

The relative difference is probably the same, but the absolute
difference has gotten smaller.

If back then it was VMS process creation 5% CPU Unix fork 0.5% CPU,
then it today would be VMS process creation 0.1% CPU *nix fork 0.01%
CPU.

>> And I believe that for true high performance then even
>> *nix are switching from traditional forking to threads.
> 
> Different tools for different jobs.  But threads are another thing that DEC
> did so much better than anyone else but then totally lost the lead on.

What are you referring to? The old CMA$ interface?

Arne