anything with a computer over 10 years old is obsolete, unmaintainable or unrepairable, and is pretty much useless.
I have used personal computers ever since they started to become popular (for me since about 1986, or just as the PC clones came out on the market).
I would have to agree with peter's statement, because for a number of reasons, PC's really don't hold up very well over time.
I have had hard drive failures, lots of memory failures, software upgrade issues, speed issues, etc.
I probably average a computer failure every three years minimum.
There is no sense repairing them; they just get tossed on the heap, or retired if the relative speed or graphics gets too slow for modern software.
I also agree with bluejets, and don't think there is any contradition, when he says "any modern day computer system or microcontroller could be adapted to suit whatever the previous application was and possibly do a better job much more quickly".
Perhaps not "any", but certainly "many".
I see it every day in industry, with PLC systems, where it is easier and less expensive to replace an entire PLC system (hardware and software) across a large facility, rather than try to upgrade or repair a 10 year old system.
Huges masses of copper wire get replaced with a single fiber-bundle cable.
Same with power distribution relays.
The big electrical manufacturers generally only support their electronics for so many years, and then you can no longer get parts, so you replace the entire relay.
For medium voltage power distribution equipment, some of the switchgear designs that I specified in 1985 are so good that they are still available and in general use today. Eaton/Westinghouse medium voltage equipment has changed little over the years.
The relays for medium voltage equipment have become very sophisticated, and now can easily communicate over ethernet.
Some folks are very into applying hardware/software to machine tools; the DRO being one application, and the CNC being another.
I guess you have to pick which methods you want to get involved in.
I prefer a manual lathe and mill, with a poor-man's DRO in the form of $20.00 vernier calipers with digital readout strapped on where most needed, such as on the horizontal axis of the lathe carriage.
If my DRO quits working, I toss it, grab another off the shelf, and am back cutting metal again in about 1 minute, for $20.00.
If I had not invested in a full-blown foundry, I probably would have invested in a good DRO for the lathe and mill.
There is only so much money I have available that has to be spread around my broad approach to the model engine the hobby, and so I can get by with manual machine tools such as Grizzly-made, but can't really cut corners on the foundry equipment.
I would like a nice mill, but I can get by with my Grizzly.
The micro-controllers for kiln control are very nice, and I have one of those.
It is difficult to heat treat aluminum castings without accurate heat control.
Luckily, gray iron castings, if made correctly, don't need any sort of heat treatment, at least as far as obtaining good machinability.
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