Good answer. A couple additional notes: the 1401's backplane was also wire-wrapped by a Gardner-Denver machine controlled by punch cards. Field engineers could

Good answer. A couple additional notes: the 1401's backplane was also wire-wrapped by a Gardner-Denver machine controlled by punch cards. Field engineers could modify the wiring with hand wire-wrap tools (to fix problems or add new features), but most wiring was automated. IBM was using CAD for their systems way back; the 1401's wiring diagrams were called Automated Logic Diagrams because they were computer-generated, originally using a vacuum tube IBM 704 or 705 computer. I'm still not sure if IBM's solid logic technology (SLT) was a good idea, or if they should have moved to integrated circuits much sooner.