APL2

APL2 can be a true gestalt

Customer: Johns Hopkins University Applied Physics Laboratory
Author: Richard Stockbridge
Country: United States of America

The Intersection of APL2 and Richard D. Stockbridge
A Respectful Testimonial

APL2 has been a necessary and sufficient programming environment in my career in science for almost thirty years. My perspectives and experiences are personal, unique and certainly orthogonal to the mainstream programming directions that evolved here at The Johns Hopkins University Applied Physics Laboratory (JHU/APL). Yep, APL at APL, a double-dose. Starting in the early '80s, there was a small group of APL aficionados at JHU/APL enamored with "Iverson's Language." We used "IBM3279" terminals and were obviously much cooler than the trudging dinosaurs who carried ten thousand IBM punch cards in cumbersome 30-inch long metal drawers and toted them to the central "computer center" for compilation. My experience started with APL(1) on the IBM 370 and Amdahl mainframes in the late '70s and moved to APL2, also on a mainframe, in the mid '80s (we operated on MVS and then VM). I used APL2 to complete the compounded numerical regression analyses and graphics for my Ph.D. dissertation and then somewhat reluctantly migrated to the PC DOS OS workstation environment shortly afterwards. It turned out that the Madrid & Manchester APL2 application was a more-than-adequate and welcomed alternative to mainframe computing, which shortly thereafter became unavailable. The current Workstation APL2 product running on Windows is simply essential to the life that I have invented and nurtured.

APL2 can be a true gestalt, a liberating computational Weltanschauung for the initiated. When practicing APL2, discovery of latent recursive algorithms frequently occurs serendipitously after data are first organized into logical, multivariate nested arrays. And recursion, as we all know, is the holy grail of algorithm development. Emergence of insightful "divide and conquer" strategies becomes inevitable once the approach is redirected top-down on suitably partitioned data. This experiential pattern suggests a unique value of APL2: it can reveal a subterranean simplicity beneath surface turbulence. Thus APL2 is discovered ex post facto to be an epistemology, a way of discovering, learning and knowing about the mechanization of problem solutions through the enlightened manipulation of data. A fluid implementation with concrete results: an ethereal anti-depressant therapy for the over-burdened and undervalued. So there you have it, the truth, the whole truth, and nothing else.

I remain grateful to the IBM Silicon Valley Lab and Manchester & Madrid Centers, and the founding fathers, Ken Iverson, Adin Falkoff and Jim Brown, for conceiving, creating and enhancing an iconoclastic mind-bender of enduring value. Your persistence and longevity have been and remain invaluable to me.