> it was easy to hear anyway

It has been very frustrating to watch designers ramping up reliance on the side channels by piling functionality into a single button at the same time as the side channels were disappearing and software latency was telescoping so that in present year I frequently have to reverse engineer morse code power button bullshit with 20 seconds of lag in the tight loop before the first audible/visible cue comes through. Is a short press 0.5s-1.5s? Or is that a long press? Is 0-0.5s ignored as debounce or is it a short press? Does a long press suffice for shutdown, or do you need a really long press to trigger hardware shutdown because the software shutdown is unreliable? Is 5 seconds long or really long? AAaaaaaaaaaa

Even in the DOS days, you still had to park the drive heads before shutting down. DOS even had a PARK command for that.

> DOS never had an option to shut down, you just saved your work and turned off the computer.

I miss this simplicity. With journaled filesystems, it should be pretty safe to do this.

Few things bother me as much as a computer that takes more than 1500ms to shut down.

I'm not even aware of anything stating it was safe to kill power inside Win 3.xx

Exiting Program Manager before flipping a power switch was always normal operating procedure.

If you killed power in Windows with no regrets you've lived a dangerous life!

Indeed. DOS had primitive disk caching, but it flushed all caches before returning to the command prompt, for continuity with the time when it had no caching at all. So if you saw C:\>, you could safely turn the computer off. You wanted to exit Windows before cutting the power.

Another wrinkle to this is that many computers' power switches were physical switches on the power supply that directly closed or opened the circuit supplying power to the computer. There was no way for the computer to switch itself off like in today's ACPI-mediated world, so the user had to be told when to turn the computer off.

Just goes to show how backward and primitive the PC was until well into the 90s. Macs had been shutting themselves off, and ejecting their floppy drives, since 1984.

Shutting down Windows 3 (mid-range) corrupted a project I had been working for months on. One still had to take care.

> that before Windows 95 the concept of "shutting down" a computer was mostly unknown.

I think you mean a "personal computer". Apollo DomainOS, at least, had a shutdown command and i presume that also VMS had one.

This message helps reinforce that shutting down the computer before seeing that message was NOT safe.

Remember that it's an all-black screen that came on after a blue cloud screen with "Please wait while your computer shuts down".

The user needed no encouragement to switch it off.

They'd spent the last 10 minutes swearing at windows for taking forever to shutdown and were about 10 seconds from saying screw it, and turning it off anyway.

This is the actual answer. If you want a computer to power itself off, you either need to design a contraption that mechanically opens a power switch, or you need a transistor that is carrying the full load of the computer at all times. It's much easier to have a switch for the human to press.

> Please power off the computer.

Sounds a bit like ordering the user, I guess that's why they went with the other message.

> Press the power button - hopefully a chunky rocker switch - and the system is off (minus the RTC battery).

My favorite part of this era were those under-monitor power switch gadgets, so you could just leave the AT power switch on as well as the printer, monitor, modem, etc. and have one master power switch that turned everything on or off.

I still have an early '90s IBM PS/1 that was my family's first computer. The only accessories that survived from then are the CH Flightstick and Gravis Gamepad, the original keyboard, mouse, and monitor are long gone (I really regret not having the wonderful original clacky IBM keyboard), but it still works and still boots off its original 129MB hard drive.

If I find one of those power switch things at Goodwill or whatever I'll pick it up without a second thought.

I wonder if one forcefully disables all ACPI support and drivers, are they allowed to go back to the binary ON/OFF lifestyle on a modern x86 system? What does Windows do?

> hopefully a chunky rocker switch

Because wall-power was routed through that switch, quite dangerously, the cable could get pinched in the case.

May I ask why you still have an XP machine running?

Some people think UX designers are useless. But they know that kind of stuff and how to make it right.

(Let's not get into the discussion that a lot of graphics designers call themselves UX experts, without actually knowing UX stuff).

> And back in the day, most computers fell into the second category. Power management was one of those newfangled thingies that only the fancy-pants computers supported.

It depends on how soft is soft and if you consider laptops to be PCs. :) At that time some models already came with a "slide once to power on, slide in the same direction again to power off"-style switch and not of the mechanic toggling kind. The APM specification also predates ATX by a few years (1992).

A favourite among some people in that era was to change the "now" to "not" and see how long it takes for someone to notice.

It was less about physical damage, and more about leaving the system in a state that couldn't boot up. In particular, incomplete writes leading to corruption of the windows registry was a frequent problem.

Yes, in some cases. The common case for this would be writing the flash chip ("Updating the BIOS"). Some boards are more cautious about this than others, and a lot of "enthusiast" (overclocker) boards have dual BIOS chips, so you can always swap to a working one and then reflash the corrupted one. But very few modern systems will tolerate a power cut in the middle of a firmware update very well, and even if it does, it's often in a "Well, now, create this particular USB stick with exactly this filename on a FAT16 partition, boot it with it plugged into this particular USB port, and it might recover things" sort of method.

You'll notice most laptops refuse to update their firmware without the battery reasonably fully charged, and the power adapter plugged in. This is why.

And then we get into the definition of "irreversible." Yes, you can recover from this with an external SPI flasher, if you can get the firmware image into the proper state for the SPI flash, or have an image from before. But most people don't have this option.

As for hard drives, I'm of the impression that most newer drives will handle a power cut by using the inertia left in the platters and the motor-as-generator long enough to drive the heads back to a safe position, but I've not done any sort of in depth experimentation on it. A drive with a parking ramp for the heads (or a parking track) has those things for a reason, and "scraping the coating as the drive spins up somewhere in the data section" isn't good for drive longevity.

> But for old PCs, the warning was always that it could also physically damage the PC

I don't remember this being true. I remember it always being about data loss.

I think it could be harm to components when you are writing in their non-volatile memory. Namely at least motherboard and GPU. Both often have flashable memory for BIOS/UEFI and VBIOS(for GPU). Interrupting power at wrong time when these are being written could result in non-functional components. Some models do offer dual-bios which lowers the risk.

In the 90s (i.e. when Windows first got this splash screen), there was no concern with physical damage - after all, in DOS, just turning it off while at the C:\> prompt was the normal procedure.

But the filesystems normally used on PCs at the time didn't have journalling or other mechanisms to prevent metadata damage if the power was turned off in the middle of a metadata update, which made data loss that much more likely even for blocks that were already written.

I think you can have problems today if you have a power failure mid motherboard firmware/BIOS/UEFI upgrade. Some mobos I heard have some protection or some way to unbrick it but it could be dangerous.

And it was a real danger before for the running sofware system, I think modern filesystems are more resilient against this sort of problem.

Never heard of actual physical damage though, but I didn't live that era much, can just barely remember the screen in TFA.

> I.e. if you yanked the power cord at some specific time, the system would take irreversible damage?

If you do it one time, no. But, I wouldn't try it too many times.

(do you know Windows 10 has "online checkdisk" - and doesn't work. Ask me how i found out)

SSDs without a capacitor bank that keeps the lights on for a bit more time after poweroff can leave their internal data structures (flash translation layer) in an inconsistent state. The effect ranges from nothing to data loss to bricking.

Because write through caches make lies out of the best operating systems.

I don't think it has anything to do with the "good old times". It is a problem that's introduced as soon as a storage medium is used. Sure, you could shutdown your C64 anytime, but even then, if you did it while it was writing to the tape/floppy, then your data was lost. And I definitely remember having to park the hard drive on an XT before shutting it down.

In the 80's, when you were in charge of your computer, if you had a hard drive and didn't park it before shutting off power, not only could you lose anything cached but not written, but you could damage the drive itself, lose all of the contents.

This is like arguing nobody is actually in charge of their bike because slamming the front brake at high speed has consequences other than stopping. It's not that we've somehow stopped being in charge of the device rather "it's going 20 mph" means there are other desires to balance beyond than "I'd like to stop immediately".

It's a good reminder that the days of yore were mostly actually pretty terrible for user control, because we're talking about a problem that currently popular computers like this cellphone and any Linux box with ext4fs no longer have. And of course before the move to Microsoft Windows around 01991 an awful lot of people were using minicomputers and mainframes they not only weren't allowed to turn off, but often weren't even allowed to see at all. A lot like AWS.

This is why I alias kill to kill -9 on all my systems.