[Info-vax] Learning VMS application programming

[Bill Gunshannon]

In article <40eb919e-9899-480c-a9e1-5a1550b738b0 at googlegroups.com>,
	johnwallace4 at yahoo.co.uk writes:
> On Thursday, 4 September 2014 13:00:24 UTC+1, Bill Gunshannon  wrote:
>> In article <121305eb-fe10-4a95-95bd-d1d0159c102b at googlegroups.com>,
>> 
>> 	johnwallace4 at yahoo.co.uk writes:
>> 
>> > 
>> 
>> > 
>> 
>> > If it worked back then, it will likely still work today. Unlike some 
>> 
>> > other operating systems, VMS has an excellent track record in 
>> 
>> > maintaining application-level compatibility across the decades.
>> 
>> > 
>> 
>> 
>> 
>> Just out of curioisty, what OS that has been around for decades do you
>> 
>> you think hasn't maintained "an excellent track record in maintaining
>> 
>> application-level compatibility"?  I can guess, but woldn't agree with
>> 
>> you.  There really are very few OSes that have been around for decades.
>> 
> 
> One example might be UNIX pre Single UNIX Specification.

Yeah, I was pretty sure that was your point.

> 
> E.g. BSD4.x vs System V R(something) vs V7, circa 1985, where they
> couldn't even agree on what the call to fd = open(name ...) was.

Only by a very long stretch of the imagination would one consider them to
be the same OS.  Unix pretty much diverged after V7 with AT&T developing
the SYSIII -> SYSV chain and BSD going in a totally different direction.
Many companies included compatability libraries to make the two look
more the same (like Sun who had SYSV libraries under SunOS and BSD libs
under Solaris), but they were two independant lines with nothing in common
but their original heritage.  

> 
> There is at least one other multi-decade option, where the OS API of
> choice sometimes changes radically from release to release.

Yeah, that one got mentioned already.  My main point was that there really
are few OSes that are still in common use that have been around for decades.
Those that are, for the most part, maintain compatability.  Some more than
others.  But I have seen more OSes go away than I have seen survive.

bill

-- 
Bill Gunshannon          |  de-moc-ra-cy (di mok' ra see) n.  Three wolves
billg999 at cs.scranton.edu |  and a sheep voting on what's for dinner.
University of Scranton   |
Scranton, Pennsylvania   |         #include <std.disclaimer.h>