Guaranteed it was very cool shit at the time! ATE test solutions were stored on mag tape, transferred to paper tape, read by the ATE. The guy writing the test solution for that device probably used an IBM mainframe, MAG tape storage, card puncher, card readers, shoe boxes full of cards or drawers of MAG tapes to store programs, fixtures, devices ... multiple revisions ... The test system likely had a wire wrap memory core programmed in machine language. Https://www.vintagecomputer.net/core-memory/ Lots of technical hurdles overcome to get to where we are today. The young have no clue.