[Info-vax] VSI: "Official 8.4-1H1 Launch"

[Simon Clubley]

On 2015-06-09, David Froble <davef at tsoft-inc.com> wrote:
> Simon Clubley wrote:
>> 
>> For one thing all the architecture specific code is _very_ cleanly
>> separated on Linux which makes it relatively easy (compared to VMS)
>> to port Linux to a new architecture.
>
> Well, I think you're missing at least one thing.  I'm guessing Linux is 
> implemented 100% in C, and if you're porting to something with a C 
> compiler, that is one big task that you don't have to do.  VMS is not 
> 100% C, and I for one think that's a good thing, and multiple compilers 
> must be ported right up front.  Now let's look at those compilers. 
> Before you're done you're going to need them anyway, because some 
> customers will need them.  (What good is a port if no customers will be 
> able to use it?)  So porting Linux and porting VMS really are two 
> separate types of tasks.
>

When you port Linux to a new environment you still have to port binutils
and gcc first if the new environment is not yet supported by them.

Once you have the language tools out of the way (and using LLVM is a
good decision of the part of VSI) the ease of porting the OS depends
on the OS internal architecture.

Yes, the fact the Linux kernel is written (mostly) in an architecture
independent language is a major benefit, but the real benefits come
from the internal Linux design, including the _strict_ isolation of
architecture specific code from the rest of the code.

BTW, I hope VSI are porting multiple compiler front ends but far fewer
(ideally one) back end(s).

> I'll also point out that the multiple languages supported on VMS is one 
> of the strengths of the OS.
>

VMS style application level multiple language support has nothing to do
with the OS implementation language but to do with the design of the OS.
You can write code in multiple traditional languages on Linux as well BTW.

I think it comes back once again to observations I've made in the past
about seeing what can be achieved in other environments and wanting to
see that for VMS as well.

Simon.

-- 
Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP
Microsoft: Bringing you 1980s technology to a 21st century world