[Info-vax] ADA and VMS (was Safer programming languages)

[Craig A. Berry]

On 11/15/21 6:35 PM, Arne Vajhøj wrote:
> On 11/15/2021 6:28 PM, Bill Gunshannon wrote:
>> On 11/15/21 4:18 PM, Robert A. Brooks wrote:
>>> On 11/15/2021 4:01 PM, Bill Gunshannon wrote:
>>>> This talk of Ada, VMS and Systems programming has raised a new
>>>> question in my mind.
>>>>
>>>> Given that Ada got it's start on VMS (one of the first validated
>>>> Ada Compilers was on VMS) has any attempt ever been made to write
>>>> any part of VMS using Ada?  Device Driver? Anything?
>>>
>>> ACME_SERVER and SECURITY_SERVER are written in ADA.
>>>
>>> Both are being rewritten in C.
>>
>> Were there ever any internal benchmarks run against them so that
>> a comparison of performance when the C conversion is done could
>> be looked at?
> 
> Depending on how many checks were disabled in the Ada version, then
> the C version may be a little or a lot faster,
> 
> But I cannot imagine it having any significance on modern hardware.
> 
> They did not rewrite in C to save CPU cycles but because they did
> not have an Ada compiler for the new platform.

Right, but that doesn't mean the performance of the Ada version is good
or that bad performance doesn't matter. In fact, ACME server performance
is pretty lousy.  SET SERVER ACME/RESTART takes 36 seconds on an rx2660.
  That's 36 seconds of downtime during which no one can log in to the
system, which might not matter much in some environments, but is still a
very long time to restart a service.