[Info-vax] Hard links on VMS ODS5 disks

[Arne Vajhøj]

On 7/22/2023 4:57 PM, John Reagan wrote:
> On Saturday, July 22, 2023 at 10:26:27 AM UTC-4, Arne Vajhøj wrote:
>> On 7/20/2023 8:49 AM, Simon Clubley wrote:
>>> I get the impression that you have had to spend a lot of effort to
>>> duplicate low-level behaviour in a way that simply isn't a concern
>>> with other operating systems due to the need, especially, to support
>>> Macro-32 and ensure that code written at this low-level, and which
>>> uses the various idioms as a result, continues to work.
>> I believe Macro-32 is a relative simple compiler. And when they got
>> that then they can compile the existing Macro-32 code.
>>
> Well, I just spit my wine out reading that.
> 
> Simple?  Try to deal with condition codes.  Try to deal with routines
> that jump between each other.  Try to make the stack "look like a VAX"
> on platforms that say otherwise. :)

OK. I was wrong. Happens all the time. :-)

>> I believe that VSI is mostly reusing existing Macro-32 code
>> and writing new code in C.
>>
> Actually there was a good chunk of Macro-32 that was rewritten into
> C.  We redid much of the memory management code for example.  It
> needed to change to deal with the more complex page table structures
> on x86, etc.  Decided to rewrite into C.

If the old Macro-32 code did not work, then doing the new code
in C instead of writing new Macro-32 code makes sense.

>> It means that changing from 32 bit pointers to 64 bit pointers is
>> way easier in C than in Macro-32.
>>
>> But based on what we know about the port, then VSI has not changed
>> the VMS kernel from 32 bit pointers to 64 bit pointers (aka moving
>> everything from S0 and S1 to S2).
> 
> Actually lots more stuff is now in S2 space and several internal pointers
> were lengthened from 32-bits to 64-bits.

Interesting.

I thought there were still room in S1.

Are you at liberty to disclose what has been moved to S2?

Arne