Could you relate how you go about fixing a DOS machine? I'm imagining that technical experts get paid a lot of money and get flown across the country to get critical assembly lines working again. Am I far off?
But a good friend of mine has a very awesome job: he is employed by a very large manufacturing company that makes consumer products. They have dozens of plants all over north america, most of which run machines from companies that are out of business or the lines are no longer supported. When one of these antiquated machines break and the on-site service techs can't fix it or don't have spares they call him in. He will basically pull an old ISA card out of a machine, troubleshoot what broke, and replace board level components. He has a stash of old harddrives from eBay. Every version of old software you can imagine. In a few cases he has made new controller boards completely from scratch (including dumping firmware off of chips and flashing it on to new ones). When you are losing $200k an hour with a line down, "screw it I'll make a new one from scratch" isn't a silly response to the plant manager.
I remember fighting to get some UPSes on important machines once upon a time. I don't remember going even one single summer without having a power outage. In fact, there were normally several per year.
When you're 'only' earning an average 20K$/h (10% profit is an ok number I would say, but it may be far less if it's a common finished good), then it may have sens not to pursue buying couples of every single spare part you should have. The full price for always having in stock working spare parts for 100% of a 3M$ production line could be well in the tens of hundreds per month. At the end you're cutting your profit and that's the last thing you want to report to the board, as a plant manager.
That guy must have had a steady hand and be really quick with the soldering iron. Making a new controller board while a 200k $ / hour line is down, well I always suspected my job was boring, now I know.
(My first real IT job was creating the DOS configurations for IBM ThinkPads at F100 corporation. Prior to that I was a total point-n-click Apple guy who was into DTP. If I could write a bullet-proof CONFIG.SYS, a lot other people could too.
Those ThinkPads were weird too, some of them had more devices than available IRQs, including a "mwave" DSP, so you had to create boot menus. Plus, they were running token ring, and there was actually a relevant difference between ISA and PC AT.)
And when I say "reimage" I mean that I'd run an XCOPY script I had that copied the last known-good backup from a Novell share, after which I'd boot from a DOS floppy and do a sys c:
I eventually made a batch file called 'fix' that would do the more common fixes and had them run that without bothering me.
I used to hate it though, as I was dealing with it at the time when Windows Server was already becoming standard in the enterprise environment.
CTRL + ALT + DELETE and a dog-earred copy of "DOS for Dummies"?
When I say "install instructions" of course, I mean they were told to type something like:
c:
cd \foo
cd \bar
cd \baz
copy a:\wuzzle.exe