[Info-vax] VMS process communication

[Simon Clubley]

On 2023-03-10, Arne Vajhøj <arne at vajhoej.dk> wrote:
> On 10/31/2022 9:06 PM, Arne Vajhøj wrote:
>> On 10/31/2022 9:18 AM, Simon Clubley wrote:
>>> Have you considered adding articles about 64-bit memory access 
>>> programming
>>> on VMS and its limits ? Or is everyone already (painfully :-)) aware of
>>> the issues involved here ?
>> 
>> I have not considered that.
>> 
>> Long opinionated writing about what DEC decided 30 years ago,
>> why, consequences of that and, discussions about whether DEC
>> made the right decision and discussions about what VSI should do
>> now are out of scope for the series.
>> 
>> And from the more practical perspective I don't think there
>> is enough to write about. One page with background,
>> one page with all the stuff one can do in C and one
>> page about the fun of Java calling C via JNI. That
>> must be about it.
>
> I decided to do it anyway.
>
> And it turned out to be more than 3 pages to write.
>
> Pre-release for comments:
>
> https://www.vajhoej.dk/arne/articles/vms64.html
>

Typo:

	"reduce memoy usage"

Generally, a well-written article.

One comment is to consider what the average person used to other operating
systems may ask and that is "why wasn't the operating system and the RTLs
simply recompiled to use 64-bit pointers instead of 32-bit pointers" ?

You have done some work at explaining this, but it doesn't state clearly
enough the real answer, which is that on VMS, pointers in the languages
and structures used to implement VMS are not hidden behind an abstracted
pointer type (ie: unsigned char *ptr), but are really just directly visible
integers (ie: uint32_t ptr).

Simon.

-- 
Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP
Walking destinations on a map are further away than they appear.