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From: Stephen Hoffman <seaohveh@hoffmanlabs.invalid>
Newsgroups: comp.os.vms
Subject: Re: SDL, SDLC, PL/I (was Re: VMS Pascal article)
Date: Sat, 4 Jan 2025 14:14:55 -0500
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On 2025-01-03 14:30:37 +0000, Robert A. Brooks said:

> On 1/3/2025 7:59 AM, Arne Vajhøj wrote:
>> On 1/2/2025 10:48 PM, Robert A. Brooks wrote:
>>> On 1/2/2025 10:32 PM, Arne Vajhøj wrote:
> 
>>>> I thought it was PL/I. Which is why I asked.
>>> 
>>> Rewritten in the early 2000's.
>> 
>> Ah. So it was rewritten for Itanium instead of being AEST'ed.
>> 
>> I wonder whether it was because someone at HP decided to do the right 
>> thing or because AEST couldn't handle it.
> 
> I am not aware of an attempt to AEST it; it was rewritten by Walter 
> Breu (sp?) of HP Germany.  He was not in VMS Engineering, so I wasn't 
> paying a lot of attention when he was doing the work.
> 
> Pretty sure it was part of the "get rid of all PL/I" initiative.

That's basically correct, yes. And Walter Breu was the author of the 
SDLC port and of some related updates. One of the goals of that SDLC 
port was character-level-formatting compatibility with the PL/I version 
of the SDL tool; matching DIFF'ing.

Various factors that triggered this port including the transition of 
PL/I to Uniprise and later Kednos — and particularly the lack of a PL/I 
compiler on Itanium — and caused an interest in reducing the usage of 
PL/I within OpenVMS. MONITOR was the biggest existing user of PL/I.

Translating the existing SDL tool to OpenVMS I64 worked, but obviously 
wasn't a great choice for maintenance and updates, and changes to SDL 
in support of Itanium were needed. And the original PL/1 SDL 
implementation also wasn't itself entirely stable. It crashed. A lot. 
And translating (AEST and TIE) an unstable app is less than fun.

There were other OpenVMS and OpenVMS build components that were 
re-written around each OpenVMS platform port too, and those rewrites 
for various reasons. MAIL got rewritten, GNM, MONITOR as mentioned, 
etc. There are undoubtedly tools that have more recently been rewritten 
as part of the x86-64 port, too.


-- 
Pure Personal Opinion | HoffmanLabs LLC