[Info-vax] [OT] Wirth style languages, was: Re: Obscure Ada compiler vendors?

[Paul Sture]

In article <kk1ch0$94i$1 at dont-email.me>,
 David Froble <davef at tsoft-inc.com> wrote:

> Keith Parris wrote:
> > On 4/4/2013 11:01 AM, Stephen Hoffman wrote:
> >> Rewriting all of OpenVMS?  That'd lead me to this state:
> >> <http://www.youtube.com/watch?v=3L6i5AwVAbs>. Even if you were to be
> >> successful with a rewrite, once you're done with that very substantial
> >> and years-long effort and investment, you would have something
> >> approximating current-day VMS. Not the features and functions that
> >> folks would would want and would expect after all those years.
> > ...
> >> The rest of the
> >> market is not standing still here, and you're talking about a project
> >> that took three or five years last time (Alpha to Itanium) for a fairly
> >> straight port with very few changes, and with an engineering team that
> >> was very familiar with VMS assigned to the effort full-time.   ~Thirty
> >> million lines of Bliss and C and Macro32 is a huge project to
> >> reconstitute.
> > 
> > By this logic, the GNU project and Linux could never have caught up 
> > with, much less surpassed or exceeded, UNIX capabilities.
> 
> Indeed!
> 
> Extend the logic far enough and perhaps we never should have left the 
> caves ....
> 
> However, the facts still are, thirty million lines of code is 
> substantial.  No way around that.  Just tossing it isn't a small step, 
> more like stepping off a cliff.

The only time I counted the lines of code I produced per month I got 
~3,000, including copious code comments, so probably way less actual 
lines of code (to compensate, there were probably hundreds of lines of 
form generator code not in that figure).  Although attention to detail 
was required this wasn't particularly difficult code, I wasn't finding 
corner cases in the compiler or dealing with timing issues for example.

I imagine that O/S code would be substantially more difficult.

Anyway, using that 3,000 lines as  ball park figure that makes 10,000 
man months, or 833 man years.

For stuff rewritten from assembler to our yet-to-be-decided HLL there 
will no doubt be a reduction in that 30 million figure, but of course we 
haven't added any new features like a new file system yet.

> But at this time, it's not even in hand to be tossed ....
> 
> Of more concern to me is VMS (as far as I know) is more of a monolith, 
> with lots of complexity and inter-relationships.  Is this reality?  Any 
> changes can have far reaching ramafications.  Is this the best way to 
> put an OS together?  I sure don't know.  But I read about micro-kernels, 
> and that path has advocates.
> 
> I'd think that a more modular approach might avoid some issues that now 
> might be a problem in VMS.  Don't really know.  I also don't know if a 
> more modular approach might be very detrimental in some ways, such as 
> performance.

I have seen systems which were over-modular and they ran so slowly that 
there was no way they would ever hit production.  The worst example did 
dozens or even hundreds of indexed reads to display each line of 15 or 
so item lines on an enquiry screen.

-- 
Paul Sture