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Comment by outworlder | Hacker News Reader

> If that 486 hardware lasted 20 years already, seems like there's a pretty good chance it'll outlast most of the modern stuff it would be replaced with.

Unlikely. Good quality 'modern stuff' has far better quality than what was available back then. Power supplies have gotten much better (and have more protections), as did motherboards with solid state capacitors. Older motherboards loved their electrolytic capacitors.

Processors had less protections. Thermal monitoring was at its infancy.

Memory sticks back then were very unreliable. As were hard drives.

Then there's just a matter of age. If it has lasted 20 years, chances are it won't last much longer.

It has probably lasted 20 years because it wasn't being powered on and off constantly. It most likely had stable power sources and - most important - a climate controlled environment with low amounts of dust.

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A 486 system was built before the capacitor plague. Quality electrolytics may not last forever, but can last a long time. Also, built before RoHS and the reduced longevity of poorly formulated or poorly applied lead-free solders that were common for many years.

Processors had less protections, and thermal monitoring was at its infancy because almost all the 486s wouldn't use enough power to cook themselves to death, even with passive heatsinks.

I don't know about memory sticks and hard drives from that period. It's quite possible they've replaced the hard drive with compact flash or something too, which should be pretty reliable given they apparently only make a floppy disk's worth of data every day.

I'd love to hear more about what "the capacitor plague" is

https://en.wikipedia.org/wiki/Capacitor_plague

It's why computers from the 80s can last until now without needing any recapping but computers from 2002 or so are ticking time bombs.

But not after 2007?

Well, for some years after 2007, you still have old stock bad capacitors floating around. And you're into lead-free solder problems.

Um.... All electrolytics eventually go bad as the electrolyte solution dries out eventually. Re-capping retro computers and radio gear from the 70s through the 90s is very much a thing.

That being said, electrolytics were somewhat less common than they are now. But the Capacitor Plague is not the only reason electronics are recapped, especially older/vintage/retro electronics.

Yeah, but the 70s-90s stuff may die /eventually/ but not pretty consistently after 2-3y, that was the point.

This! Got a used AMD-K5 PR133 in a big-tower a long time ago, integrated it into my home lab, and used it to experiment.

About 1 one year later it underwent my cleaning routine, vacuuming dust out, cleaning the fans, etc. I took the cpu-cooler off to check for bad thermal grease and discovered it had none at all! No pad either, someone just clipped that thing on, and instead of direct contact it had a small airgap which you could look through from the sides.

Unbelievable.

When I got it, it must have been in use for years already!

Modern components are run much closer to their limits, simply due to engineering optimisations.

A 486 doesn't even need a heatsink, it's passively cooled and perfectly fine with that, as software of the time (mainly DOS) didn't even "idle" the CPU --- it was drawing full power all the time.

That also means if you manage to boot DOS or similar era software on a modern machine (especially a laptop) that was designed to have the CPU idled for most of its life, it is likely to go into thermal throttling immediately.

Is that really true? I booted FreeDOS (had it installed for a while just for kicks) on my Thinkpad T420 (i5-2540M) and I didn't notice any heatup.

Yes and no. The 8086 had a HLT instruction that was meant to replace the busy loop waiting for an interrupt. It was soon understood that you could also save power by turning off the clock. I'm not sure if the "SL" versions of the 486 turned off the clock with the HLT instruction, but later versions did. Use of it was apparently introduced in MS-DOS 6.0, so FreeDOS, Windows 95 and OS/2 2.1(?) would have probably used the instruction to effectively idle the processor. Not sure if Windows 3.1 made use of it, but it would make sense as the basis of the system's event loop.

https://en.wikipedia.org/wiki/HLT_(x86_instruction)

I recently installed DOS 6.22 (and Windows 3.11) in a VM and it causes one core to sit at 100% all the time.

I don't know if the VM changes anything, but it definitely seems as though it does not halt while waiting for activity.

I can recall there were programs like "Waterfall" and "Rain" which were supposed to force Win9x to HLT when idle.

Besides what the sibling reply mentioned about capacitors and processors, WRT memory that machine has survivorship bias. The fact it's been running for thirty years tells you the RAM in the machine is good and is unlikely to have a problem barring damage. The same is true for all the other still working components.

True, but people have backported modern hardware to that era. You can take a modern power supply and drop it into that PC, I'm almost sure.

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