[Info-vax] OS Ancestry

[Arne Vajhøj]

On 5/17/2021 9:20 AM, Dave Froble wrote:
> On 5/17/2021 8:18 AM, Simon Clubley wrote:
>> On 2021-05-15, <kemain.nospam at gmail.com> <kemain.nospam at gmail.com> wrote:
>>> Another pretty good link for those looking for VMS history:
>>>
>>> <http://gordonbell.azurewebsites.net/digital/Bell_Retrospective_PDP11_paper_ 
>>>
>>> c1998.htm>
>>>
>>> "A Retrospective on What We Have Learned From the PDP-11:
>>> What Else Did We Need to Know That Could Have Been Useful in the 
>>> Design of
>>> the VAX-11 to Make Alpha Easier?
>>>
>>> "VMS is the Architecture That Mattered. not PDP-11, VAX, or Alpha"
>>>
>>
>> From that link:
>>
>> | Thus, our real oversight was not understanding that VMS should have 
>> been
>> | built on the C machine for portability across any architecture.
>>
>> This. 5 zillion times this. VMS could have become like Unix in dominance
>> if this had been the case.
>>
>> Want to move VMS to a new architecture in this setup ? It would have been
>> a comparable effort to what is involved in porting Linux to yet another
>> architecture, instead of the current effort that is involved.
>>
>> VMS was designed at too low of an abstraction level.
>>
>> Also, while he mentions BLISS, he skips over all the Macro-32 usage
>> and, based on discussions here, all the internal calling conventions
>> within the VMS kernel that requires those registers.
> 
> But is the implementation language the only issue?  I'd think not.  As 
> John and minions have demonstrated, perhaps with some effort, they can 
> handle the multiple languages.
> 
> Rather, perhaps it is the concepts that are different enough that it's 
> apples and oranges, not two different types of apples?
> 
> For an example, FORK doesn't seem too easy to implement on VMS, 
> regardless of the language.  Though, I'll admit that this example has 
> little to do with your claim of ease of porting.

Given that it looks like the treading model has won over
traditional forking, then I don't think the missing fork
was the problem.

Arne

PS: Note that I used the term "traditional forking" not just
     "forking" - I believe on Linux then threads are implemented
     using fork mechanism under the hood.