My first job out of uni was working for IBM fixing 029 and 129 card punch machines,
Wow, so you worked on essentially the LAST (most modern) generation of card punch machines.
By the time IBM came out with those models, there were already CRT-based terminals taking over the industry.
When I was in college (late 1960s), we were phasing-out the "unit-record" card-based workflow.
We had a room full of Selectric typewriter-based terminals to program in "APL" https://en.wikipedia.org/wiki/APL_(programming_language)
Hey, I remember old APL! The IBM 5110 predecessor to the PC had APL built in.
We used to call card punches and verifiers, "crunches and terrifiers". But they were not as much fun as working on the unit record "old iron" equipment. The 129 was the last of the 80 column card punches, but IBM did make a machine called the 5496, a 96 column version in the early 1980's. Myself and another engineer were the last people in Australia to be fully trained by IBM on unit record in Australia. As you suggest, the crunches and terrifiers were replaced by 3741's and 3742's which were CRT based programmable data entry machines, using an 8 inch single sided 160kB diskette drive.
The first hard disk I worked on was a 5.1 MB Winchester which was so big and heavy it took two men to lift it. It was used in the IBM System/32 and cost around $100K in today's money as a replacement. The IBM System/38's 3370 DASD (Direct Access Storage Device) disks were 700MB, as big as a washing machine, and cost around $200K each in today's money. Today, 2,000,000 MB Seagate Barracuda drive costs under $100. That's around 400,000,000 times increase in cost per byte compared with the System/32 hard disk. Mind blowing to us veterans, but young adults and teenagers today think of it like this...
![Confused :-//](https://www.eevblog.com/forum/Smileys/default/confused0024.gif.pagespeed.ce.5xOqKkq0Co.gif)
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People have it easy these days. Drive breaks... throw it out. No need to know how it works. No need to be even interested or excited. Same with Intel's PC processors. Most people have no idea how they work. And they don't need to. Sadly, it appears teenagers today have lost the "WOW FACTOR" that we had when we were teenagers. I found the wow factor with ham radio around 1977, via CB radio, and got my license in 1982. Even today, I still find there is magic in HF. Most engineers today don't even know what ham radio is. And for them there is no wow factor.
IBM's unit record manuals were superb in quality, but they did not find the faults for you. It required diagnostics skills which I struggled with when I started at IBM, but over several years the brain wired itself to be pretty good at diagnosing faults in pretty much anything including TV's and video recorders, preferably with the help of a schematic diagram. These days I do design & development work in electronics (medical) but the experience from the old iron days is still very useful.