[TUHS] long lived programs (was Re: RIP John Backus

[Larry McVoy]

I'm really not worried about it.  When I got into kernel programming
I had no idea what I was doing.  I just kept at it, did small stuff,
the bigger picture slowly came into focus.  After a couple of years there
wasn't much that I wouldn't take on.  I stayed away from drivers because I
had figured out that Sun had their stuff but it was going to be different
than SGI's stuff and both different from PC stuff (even the PC stuff was
different, I would have been working on ISA bus devices and that's long
gone so far as I know).  But file systems, networking, VM, processes,
signals, all of that stuff was pretty easy after you got to know the code.

Every year someone takes some young hotshot and points them at some
"impossible" thing and one of them makes it work.  I don't see that
changing.

On Fri, Mar 23, 2018 at 12:28:47PM -0700, Bakul Shah wrote:
> On Mar 22, 2018, at 2:35 PM, Clem Cole <clemc at ccc.com> wrote:
> > 
> > The question (and a good one) is if you are not 'a Fortran person,' are you going to be able to understand it well enough to not do damage to it, if you modify it?  Which is of course the crux the question Bakul is asking.
> 
> This is indeed the case, but I am asking not just about 
> Fortran.  Will we continue programming in 50-100 years in
> C/C++/Java/Fortran?  That is, are we going through the
> Cambrian Explosion of programming languages now and it will
> settle down in a few decades or have we just started?
> 
> > I suspect, it is not as bad the science fiction movies profess.   Because the codes have matured over time, which is not what happened with Y2K.   Are their 'dusty decks' sure - but they are not quite so dusty as it might think, and as importantly, the code we care about are and have been in continuous use for years.  So there has been a new generation of programmers that took of the maintenance of them.
> 
> Perhaps a more important question is what % of programs are
> important enough and will be around in 50-100 years.
> 
> On Mar 23, 2018, at 3:43 AM, Tim Bradshaw <tfb at tfeb.org> wrote:
> > 
> > My experience of large systems like this is that this isn't how they work at all.  The program I deal with (which is around 5 million lines naively (counting a lot of stuff which probably is not source but is in the source tree)) is looked after by probably several hundred people.  It's been through several major changes in its essential guts and in the next ten years or so it will be entirely replaced by a new version of itself to deal with scaling problems inherent in the current implementation.  We get a new machine every few years onto which it needs to be ported, and those machines have not all been just faster versions of the previous one, and will probably never be so.
> 
> By now most major systems has been computerized. Banks,
> govt, finance, communication, shipping, various industries,
> research, publishing, medicine etc. Will the critical
> systems within each area have as many resources as & when
> needed as weather forecasting system Tim is talking about?
> [Of course, the same question can be asked in relation to
> the conversion I am wondering about!]
> 
> On Mar 23, 2018, at 8:51 AM, Ron Natalie <ron at ronnatalie.com> wrote:
> > 
> > A core package in a lot of the geospatial applications is a old piece of mathematical code originally written in Fortran (probably in the sixties).   Someone probably in the 80???s recoded the thing pretty much line for line (maintaining the horrendous F66 variable names etc???) into C.     It???s probably ripe for a jump to something else now.
> >  
> > We???ve been through four major generations of the software.    The original was all VAX based with specialized hardware (don???t know what it was written in).    We followed that on with a portable UNIX (but mostly Suns, but ours worked on SGI, Ardent, Stellar, various IBM AIX platofrms, Apollo DN1000???s, HP, DEC Alphas).   This was primarily a C application.    Then right about the year 2000, we jumped to C++ on Windows.    Subsequently it got back ported to Linux.     Yes there are some modules that have been unchanged for decades, but the system on the whole has been maintained.
> 
> I wonder if we will continue doing this sort of adhoc
> but expensive rewrites for a long time.... 
> 
> [This may be somewhat relevant to TUHS, from a future
>  historian's perspective :-)]

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Larry McVoy            	     lm at mcvoy.com             http://www.mcvoy.com/lm