On this day: May 3

Early concept of a self-replicating computer program outlined

On May 3, 1983, researcher Fred Cohen published a formal analysis describing self-replicating programs—what would come to be called computer viruses—marking one of the first large-scale conceptual treatments of the idea.

Early concept of a self-replicating computer program outlined

On May 3 (year uncertain), a pioneering description of a program capable of producing copies of itself was circulated, marking an early articulation of self-replication in computation that influenced later work on viruses and automata.

First Durable Heart Valve Replacement Performed, 1962

On May 3, 1962, cardiac surgeons achieved the first widely recognized successful replacement of a diseased heart valve using a prosthetic device, marking a major milestone in cardiac surgery and transplantation of mechanical valves into human patients.

First Modern Public Housing Development Opens in 1936

On May 3, 1936, the first large-scale modern public housing development in the United States opened, marking a shift toward federally supported, planned housing for low-income urban residents amid New Deal reforms.