Operating Systems

In today’s team-oriented world, it’s the rare project that runs on one person’s inspiration and perspiration. Equally uncommon are development results that shape technology, affecting how companies, developers, application users and consumers work.

The REXX programming language was such a project, conceived and implemented by Mike Cowlishaw, now an IBM Fellow. This title is an executive-level scientist/ engineer/programmer position, the technical-side pinnacle of IBM’s dual-career ladder. The few dozen CEO-appointed Fellows pursue self-directed projects for renewable five-year terms; they serve as corporate consultants and mentors, and report yearly on activities.

Mike joined IBM in 1974, working on hardware and software products and interests such as the human-machine interface, programming languages and editors. Around 1980, he designed and developed REXX, “driven by the desire to make programming easy.” Documented before it was developed and shaped by extensive internal user feedback, it quickly grew in popularity within IBM. Customers learning of it clamored for its release; it shipped in 1983’s VM/System Product Release 3, and then was ported to MVS and VSE. Now a key resource on all IBM computing platforms, REXX is also available on most other computing platforms. Senior consultant/programmer/trainer, Chip Davis, remarks, “As soon as I installed REXX on our VM system, all [languages] but Assembler became superfluous. They have been the only two guns in my holster for the last 20 years.”

Returning to his interest in editors, Mike developed Lexx, a specialized (syntax- directed color-coding) editor for Standard Generalized Markup Language (SGML) text of the Oxford English Dictionary (OED), second edition. Lexx and its derivatives are part of IBM’s VisualAge products, and Lexx itself recently became available for free download. The OED acknowledges Mike twice—for Lexx and editorial contributions; he still consults for the OED. Mike led IBM’s technical assessment of Java and created NetRexx, a Java platform REXX version.

Mike’s books, The REXX Language and The NetRexx Language, and www2.hursley.ibm.com/rexx/ provide extensive REXX information. In this interview, Gabe Goldberg, co-editor of McGraw-Hill’s The Rexx Handbook, talks with Mike about his eclectic and evolving interests and perspectives on technology and the industry.

z/Journal: When did you realize the scale on which REXX would succeed?

Mike Cowlishaw: I suppose it was when the VM development group decided to add REXX to CMS before they had even shipped EXEC 2.

z/Journal: What would you do differently if you could do REXX and NetRexx again?

MC: Well, NetRexx really gave me the chance to correct the things in REXX that I wanted to correct, such as case-independent comparison and the keyword LOOP for do-loops.

z/Journal: What’s the most surprising platform to which REXX has been ported?

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