IBM 405

The 405 Alphabetical Accounting Machine arrived in 1934 and was, in practice, IBM's entire product line. It read a card deck, added selected fields into its counters and printed the result with subtotals — all of it directed by a plugboard where the operator ran patch cords between card columns and print positions. The program was therefore a physical object, lifted out of the machine and hung on the wall until the job came round again.

The novelty was in the name. Earlier tabulators printed digits, which is fine for a total and useless for a payroll where someone has to have a name. Alphabetic printing turned the machine into something you could keep records on rather than merely compute statistics with, and the timing was improbable: US Social Security arrived in 1935 and required running accounts for twenty-six million workers. IBM took the contract. The machines went out on rental and were never sold, which is why the revenue kept arriving long after any given 405 had paid for itself several times over.