legacy code · unmeasured

a system whose parameter window no living maintainer has measured, still inside it, maintained without knowing where its walls are.

Legacy code (noun) means: a system whose parameter window no living maintainer has measured, still inside it, maintained without knowing where its walls are. It emerges from window, wall, parameter, maintenance: The interaction of maintenance, unmeasured boundaries, and the absence of a cognitive model of those boundaries allows the persistence of a system in ignorance of its own limits. In the EmergenceLexicon it sits at computed level 15, chaining down to the four foundations (space, time, energy, pattern).

Examples

• The Therac-25 radiation therapy machine malfunctioned in 1985 due to unmeasured race conditions in code originally written in the 1970s. computing
• The New York City subway's signal system, largely unchanged since the 1940s, runs trains with timetables adjusted by hand-drawn chalk logs. engineering
• Farmers in the Sahel maintain irrigation ditches laid during French colonial rule, though no one recalls the original grading specifications. institutions

Emergence

Chain to foundations

Neighborhood

Concepts that depend on this one above; what it is built from below.

Provenance