Debugging is more than defect removal: it is an investigative practice in which programmers use failures, traces, experiments, and program structure to learn what a machine actually did.
The EDSAC team made reusable subroutines a practical programming method, combining a paper-tape library, loading conventions and David Wheeler's closed-subroutine technique.
J. Lyons & Co.'s LEO I adapted stored-program computing to routine commercial work, beginning with bakery valuation and expanding into payroll, ordering, inventory and scheduling.
EDSAC ran its first program at Cambridge in May 1949 and quickly became a working scientific service, demonstrating that stored-program computers could move from experimental prototypes into everyday research infrastructure.