[Info-vax] Userland programming languages on VMS.

[Bill Gunshannon]

On 1/31/22 19:53, Johnny Billquist wrote:
> 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.

But if you moved to a system with a large address space would
an MMU even be necessary?  BSD on the PDP_11 uses overlays,
the VAX does not.

bill