Comment by mschaef

I have a lot of fondness for the language. When I was in college, there were a series of three 1-hour language intro courses. (C++, Lisp, and Fortran). I took all three. Lisp is the only one I use these days, but the Fortran class made an impression.

It was one of the last courses, and we were discussing optimization techniques for matrix multiplication. There were the usual three nested loops and the instructor started talking about memory access patterns and stride through the arrays. He re-nested the loops, showed the improvement in access patterns, and pointed out that the compiler itself could do that automatically. (Not to mention vectorize, etc.)

This was around mid-90's, and it gave me a strong appreciation for the fact that simpler languages can be easier to reason about, transform, and optimize. If I'd spent most of the class wondering why the language was as limited as it was, that one session gave a good explanation why it could be viewed as a strength.

Parallel to all of this, I worked a few summers for a major electric utility company. They had a cluster of Cyber mainframes (Descendents of the CDC 6600) that they used to run the grid in real time. Everything was in Fortran (77?), and the shop had a number of people well versed in the language. I didn't a whole lot of direct experience, but it was interesting to see. One thing I do remember is that the memory/disk layout of the data structures were fixed at build time. They ran quarterly builds to update the layouts to add fields, etc. and made do in the interim. Between the constraints of the language, the hardware limitations, and the need for hard real time requirements, there wasn't a lot of room for flexibility.