Milton Thrasher's "Green Card Genesis"

The document recounts the origin and impact of the IBM "Green Card," a compact reference guide for the IBM System/360 (S/360) instruction set. The card was created by the author during his 36.5-year career at IBM, where he worked in the Eastern Region as Manager of Systems Engineering Techniques Development (SETD).

Key Highlights

Background & Purpose

The Green Card was developed out of the need for a convenient, accessible reference tool for programmers working with the complex S/360 Assembler Language. It originated from appendices in bulky System Reference Library (SRL) manuals.

Project PAT/360

While working on PAT/360—a streamlined automated testing tool for S/360 programs—the author and consultant David Goldstein made significant contributions. Their tool simplified the testing process for customers, especially at the Time Life Data Center, and was widely adopted despite internal IBM politics favoring the more complex AutoTest/360.

Innovation Process

The first versions of the Green Card were printed informally, evolving through feedback from users. Eventually, it was formally typeset and printed by IBM’s Technical Publications Department. The name "Green Card" stuck due to the card’s chosen color.

Resistance & Recognition

Despite strong customer adoption and success, the Green Card and PAT/360 faced resistance from IBM headquarters because they were unsanctioned projects. However, internal supporters and recognition from high-level IBM executives allowed the work to continue.

Legacy

The Green Card became a staple for programmers working with S/360, handed out in classes and widely used under glass desktop covers. The document positions its creation as one of the author’s most significant contributions to IBM.