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

[Arne Vajhøj]

On 11/15/2021 8:44 PM, Bill Gunshannon wrote:
> On 11/15/21 7:35 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.
> 
> I realize all that.  I would just like to see some comparisons.
> I don't know that any were actually done.  It all goes back to
> a comment I got from someone from the Ada Users Group about 30
> years ago.  I mentioned an interest in a version of Unix rewritten
> in Ada and was quickly informed that while it could be done it
> would result in a useless operating system because the Ada version
> would be very inefficient.  Needless to say, I never tried it.
> Might be fun to dig up some benchmarks and try it, but I always
> prefer real world examples to contrived benchmarks.

But there are two very different questions here.

Would Ada vs C for OS mean something 30 years ago (VAX 6000 and 3000)?

Would Ada vs C for OS mean something today (16/24/32 core x86-64)?

Arne