Amidst academic societies and agencies that accredit computing education there is a growing enthusiasm to reexamine the efficacy of the traditional model of curricular description that focused on areas of knowledge. The knowledge model informed the architecture and design of programs of teaching and learning in post-secondary, degree-granting institutions. The incipient enthusiasm for change draws on a vocational heritage focusing on job performance together with outcomes-based and task-centered learning and assessment, competency. Competency's emergence is fueled by a waning confidence in the cost-effectiveness of college-based education, an industry perception of a persistent short-fall of technology-savvy hiring prospects, and the efforts of governments worldwide encouraging the alignment of public education with economic and workforce policy. The competency model represents the consequence of learning as a blend of knowledge, skills, and disposition -- "'knowing' what," "'knowing' how," and "'knowing' why." The "knowing" is task-focused both as the learning "in doing" and the assessment as demonstration "in doing." Coincidentally, ACM and IEEE have undertaken to reprise CC2005 with the goal of an online interactive curriculum modeling tool for comparing and exploring curricular guidelines and academic programs. We explore the competency-based curricular approach situated in a) the history of computing curricula standardization, b) its heritage in education originating with clinical and professional disciplines, and c) its implications on the CC2020 project's aspirations of designing a "tool" to facilitate current and future competency-based computing curricula development.