Delete comment from: Ken Shirriff's blog
I served in the USAF from 1967 through 1970 as an electronics technician. During technical training (1967) one of my instructors told a story about his job experience prior to enlisting. He worked for Allied Electronics in Chicago as part of the crew that maintained the company's IBM mainframe. I can't recall the model number but it was a vacuum tube machine. Part of this fellow's job was testing (in place) vacuum tubes to evaluate if they were reaching end of life. If a tube required replacement then he'd pull and replace it, all without removing power. This technique was possible because of built-in error detection and correction. I think this must have only applied to what we'd consider data busses rather than logic circuits, but 54 years later I'm no longer clear on the exact details.
Jan 24, 2021, 11:07:47 AM
Posted to Examining a technology sample kit: IBM components from 1948 to 1986