[Info-vax] PL/I (Re: VMS Software needs to port VAX DIBOL to OpenVMS X86 platform)

Arne Vajhøj arne at vajhoej.dk
Tue Jan 5 20:59:50 EST 2021


On 1/5/2021 8:42 PM, Tim Sneddon wrote:
> Arne Vajh??j <arne at vajhoej.dk> wrote:
>> On 1/5/2021 2:05 AM, Tim Sneddon wrote:
>>> Craig A. Berry <craigberry at nospam.mac.com> wrote:
>>>> The folks making money from PL/I on OpenVMS Alpha did not see a business
>>>> case for porting it to Itanium almost 20 years ago,
>>>
>>> There absolutely was a case.  Unfortunately, there was also an expectation
>>> that somethings should come for free.  That something being the GEM backend.
>>> PL/I uses the BL 21 release of GEM (with some other tweaks from later
>>> versions).  However, there were some big changes in GEM that broke things
>>> so much so that Ada didn't move forward either.  By the time Itanium
>>> happened GEM development had moved on and little thought was given to all
>>> the annoying things that PL/I needed.  So, a PL/I on Itanium either needed
>>> a retargetted compiler or development to bring the VMS code-base to a
>>> later GEM an then a move to GEM on Itanium.
>>>
>>> I proposed retargetting the UNIX compiler to LLVM and moving forward.  This
>>> was knocked back because the opinion was that HP should provide the GEM
>>> backend, etc. for free.  There was nothing technical about the decision
>>> at all.
>>
>> Targetting JVM (or CLR for non-VMS) may have been a wise move.
> 
> There was discussion about targetting JVM too, I did some preliminary
> work there.  While it was a fun exercise heading to LLVM is a smarter
> idea and has it's own JIT, even back in 2010.
> 
>> That would have solved the platform problem.
> 
> What platform problem?  Retargeting a compiler is part of maintaining a
> compiler, it is a completely expected and accepted task.

Sure.

But if it had outputted Java byte code or CIL then you would
not need to do anything.

>> Obviously there is also some potential problems. How common was
>> it for VMS PL/I program to call LIB$/SYS$ or link with Macro-32/C code?
>>
> 
> Some? Try heaps.  PL/I code, like any other VMS application calls
> LIB$ and SYS$ (and other multi-language libraries).

OK.

I know very little about PL/I usage.

I always imagined it being pure business applications, all PL/I,
only database access and standard PL/I RTL.

Arne





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