Plug Boards: Precursors To Software
IBM corporate archivist Paul C. Lasewicz holds a plug board, which is the equivalent of software for the Type 405. Companies would have racks full of plug boards, with each board wired to support a particular type of report--payroll, revenue, stock control, and so forth. Punch cards, seen in the input and output trays of the accounting machine, stored the transactional data, such as employee hours, sales, and orders. Accounting machines had no stored memory, so they were still tabulating devices rather than computers.