[TUHS] Do Interface specifications such POSIX or the LSB Still Matter

[Clem Cole]

On Sat, Feb 17, 2018 at 8:01 PM, Larry McVoy <lm at mcvoy.com> wrote:
>
> I really don't see why.  I can see why if they are using every library
> known to man, but if you want portable you don't do that.
>
​The ISV's customers are interesting in getting a specific job done - be it
a simulation, ​

​geo or therma prediction.  Time to money is what matters to the end user -
so they pick the 'best' product to do their job.   ​Hence, e
xecution speed is typically the prime directive for an ISV like this and
they are using Fortran for portability.​ Which is different from your
design point I suspect.   You need to be fast enough, but the choice of
bitkeeper vs cvs vs ... is likely made with a different high order bit.

​For the ISV​, at a
 minimum, it is a testing issue of the different perminations.  They need
to be fast, but their production code is deployed a top of 'a stack of
turtles.'   As I said RH Linux != SuSE != Ubuntu (they are similar but the
kernels are not the same and the system DB's vary -- those tend to cause
installation issues).  GFortran != Intel ifort != PCG FTN != Cray FTN !=
IBM fortran. Much less GCC != Clang != Intel​ icc != IBM CC - cause
interesting issues with dynamic loading.   IBM MPI != HP MPI != OpenMPI !=
Intel MPI  etc..tend to cause ISV code to step on each other.
​
Then you add  Mellanox IB is not IBM is not Intel and ....
Mellanox Verbs is not Cisco Verbs is not PSM is not OFED
​ and locking and scaling starts to get strange​
.

Each of these can be a 'little different' even though they all follow
standards.  It becomes a old Al Haig - style - "I'm in charge" problem.
Moreover, I know of one large distro insists on only testing their IB stack
point to point with two system, even when they have been offered a HW from
a
vendor
​ that has 4 compute nodes plus a head node, just to chase and tease out
the corner cases that drive the ISV mad.

​
ᐧ
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