[ExI] Old Programming Languages

[Keith Henson]

I happen to post on a closed list that is full of historical figures
from the dawn of the computer era.  There has been recent discussion
about "vintage" computer languages.  Though it will probably be
gibberish to the younger members of this list, here is my
contribution:


By local standards, I am a lightweight in the programming business and
the U of Arizona where I went to school was a relative backwater.  In
1960, they had an IBM 650.  For a first-year class we wrote a simple
program in a course called "numerical analysis" and (by lot) one class
member's program (in SOAPX* as I recall) was run.  Dropped out for a
few years to work for Heinrichs Geoexploration Co., mostly running
resistivity and induced- polarization surveys.

When I went back to school, a two-unit FORTAN course had been added as
a requirement for EE's.  Later learned assembly (for embedded systems)
and C/C++ for debugging the garbage collector for Xanadu on my own,
but FORTRAN was the only actual programming course I had.  I was
hooked and looked for something to do beyond the course work.

The prototype cases we used for interpreting plotted field geophysics
data were hard to calculate by hand and only a few of them had been
done.  The solutions were Bessel functions of moderate complexity
approximated by infinite series.  Some of the cases converged very
slowly, making accuracy of the solutions a big problem.  I got one of
my old math professors to help place error bounds as a function of the
convergence of terms.

There were 8 or 9 cases that merged into each other when an electrode
was right on a boundary between materials of different resistivity.
That provided some degree of assurance (when the output matched) that
we had the math and programming correct.

The work was started on an IBM 7090 class machine and finished on a
CDC 6400.  The company burned through several thousand dollars worth
of computer time, but we sold enough copies of _Theoretical Induced
Polarization and Resistivity Response for the Dual Frequency System
Collinear Dipole-dipole Array_: Volume 1 & 2 Heinrichs Geoexploration
Co. by Chris S Ludwig, H Keith Henson to make a profit.  I think I
permanently stretched one arm from carrying around a 3/4 full box of
cards.

Keith

*http://en.wikipedia.org/wiki/Assembly_language#Historical_perspective