[Info-vax] Userland programming languages on VMS.

[Johnny Billquist]

On 2022-01-31 22:17, Bill Gunshannon wrote:
> On 1/31/22 14:43, Simon Clubley wrote:
>> On 2022-01-31, Bill Gunshannon <bill.gunshannon at gmail.com> wrote:
>>> On 1/31/22 09:02, Simon Clubley wrote:
>>>> On 2022-01-31, Arne Vajhøj <arne at vajhoej.dk> wrote:
>>>>>
>>>>> I would run Solaris on SPARC and I do run VMS on Alpha
>>>>> and keep Linux on x86-64. Are there any benefits
>>>>> from running Linux on a less common platform?
>>>>>
>>>>
>>>> One of the reasons Linux has taken off is that you can run it on
>>>> pretty much every single thing that is physically capable of hosting
>>>> it in terms of CPU power and memory/other resources.
>>>>
>>>> This includes large mainframes all the way down to tiny embedded boards
>>>> running on some custom hardware/architecture.
>>>>
>>>
>>> The same is probably true of just about any OS.  All it takes is
>>> access to the source and a desire by someone to do the work.  Why
>>> do you think I would still like to see the source to RSTS released
>>> into the wild.  RSX which was very PDP-11 specific now has a version
>>> running on later Z80 family processors.  I have it running here at
>>> my home and it works quite well.
>>>
>>
>> The OS needs to be designed to be portable and also with the architecture
>> specific features abstracted away into a lower level as much as possible
>> to stand any chance of that being true.
> 
> You must have missed it.  RSX was not designed to be portable but
> someone was able to build a clone on the higher end Z80 family.

No. It's not a port. It's a reimplementation.
Which is not even compatible in any meaningful sense of the word.

>> Linux was designed for that (and so were OS options such as the various
>> dedicated embedded operating systems). Windows NT was also originally
>> designed somewhat with portability in mind as well.
> 
> Linux was designed (if you can even say that) to imitate Unix,
> nothing more.  I seriously doubt Linus Torvald had any idea
> that it would be running on anything other than Intel at the
> time he was writing it.

Correct.

>> The DEC operating systems however were not designed with that level
>> of portability in mind due to the era in which they were designed.
> 
> And yet we have a clone of RSX and if I had the sources available
> to me we would also have a clone of RSTS.  And, if anyone was really
> interested, I expect RT-11 could be cloned in a very short time, too.

We covered this a long time ago. You don't need the RSTS/E sources to 
write a new implementation of it. You just need time and energy.

Same as for that Z80 RSX implementation.
It's not a "clone". There are significant differences. Not the least 
because the hardware is very different.

> Seriously, it's not rocket science.  Unless one deliberately made the
> hardware obscure and obtuse the OS is really going to be something
> any CS grad could deal with.  The only thing protecting proprietary
> OSes is obscurity and a total lack of interest.

Actually, making use of hardware specific features can be a big issue. 
With RSX, plenty use is made of the MMU and you have basically no chance 
of "porting" RSX to anything that don't have a very similar MMU.
Instead you will then need to do a reimplementation where some things 
needs to be done rather differently.

   Johnny