PAST PRESENT AND FUTURE of the Mainframe With Open Source BY JOHN MERTIC ast spring, state governors from across the United States called for help with COBOL programmers. This desperate need for COBOL help showcased just how dependent we are on mainframes and how relevant they are. Many technologists today are less familiar with this architecture and ecosystem, but that is changing with open source becoming a core piece of the mainframe ecosystem. What Is Old Is New L Ask someone who has been working with mainframes for some time, and they will tell you that the technology trends we see today have direct lineage to the mainframe. Virtualization? That was a feature in VM/370. Containerization? Concepts developed for mainframes and in production use as early as the 1970s. The list goes on and on. Even open source traces its root back to the mainframe. SHARE, which is the earliest computing user group, formed in 1955 in Los Angeles as a forum for users of a new piece of technology, the IBM 701 computer system. This group had the same characteristics of what we would consider an open source project today; collaboration and sharing of source code, knowledge sharing and a “community” that supports and evolves. Even the slogan for SHARE; “SHARE is not 20 | Enterprise Executive | 2021: Issue 4 an acronym; it’s what we do.”—encapsulates modern open source decades before the free software movement and the coining of the term open source in the late 1990s. This collaboration, which one might compare to what one would call “hacker communities” today, still lacked that sense of organization and centralization for the code being written. Enter CBT Tape, which in 1975 created one of the earliest known open source projects (again well before open source or even free software was a thing). This was the work of Arnold “Arnie” Casinghino, who was a steward of the tape for many years to follow, was named after his employer at the time, Connecticut Bank and Trust. The project was simple. Pull together all these tools and utilities created among this community of mainframe operators, and produce a canonical tape on a regular basis for use by the broader mainframe community. How did one get this code? On tape, of course, which you can still request today (and, of course, one can download it or request a CD-ROM ). While open source licenses were not a thing then, there was one key principle for all the code and utilities on the tape; they needed to be available free of charge for anyone to use. This principle helped the popularity of the CBT Tape grow, which continues to this day; nearly 500 releases after