[Info-vax] Userland programming languages on VMS.

[Dave Froble]

On 1/31/2022 8:31 PM, Bill Gunshannon wrote:
> 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
>
>

There is a system that runs RSX without overlays.  It's called VAX/VMS.

Don't people ever wonder what DEC people were thinking when they wrote VMS?

-- 
David Froble                       Tel: 724-529-0450
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