[HN Gopher] Why is there a screen that says "It is now safe to t...
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Why is there a screen that says "It is now safe to turn off your
computer"? (2016)
Author : susam
Score : 35 points
Date : 2025-02-16 20:08 UTC (2 hours ago)
(HTM) web link (devblogs.microsoft.com)
(TXT) w3m dump (devblogs.microsoft.com)
| gnabgib wrote:
| (2016) Discussion at the time (99 points, 44 comments)
| https://news.ycombinator.com/item?id=11527671
| accrual wrote:
| These shutdown splashes are one reason why I enjoy working with
| AT motherboards, those with the old P8 + P9 power connector ("red
| to red and it's dead").
|
| There's some charm and nostalgia in the computer only having two
| states - on and off. No standby power, no S1-S4 states, no wake-
| on-LAN, no management engine, etc. Press the power button -
| hopefully a chunky rocker switch - and the system is _off_ (minus
| the RTC battery).
|
| I have an XP machine running on such a motherboard and it too
| supports the "safe to shutdown" splash. Hibernate also works, so
| if I really want to, I can put it to "sleep" with no power at
| all.
| wolrah wrote:
| > 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.
| dist-epoch wrote:
| > hopefully a chunky rocker switch
|
| Because wall-power was routed through that switch, quite
| dangerously, the cable could get pinched in the case.
| jwineinger wrote:
| May I ask why you still have an XP machine running?
| 1970-01-01 wrote:
| 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?
| m348e912 wrote:
| The issue I have is the wording.
|
| The problem really comes down to the fact that windows couldn't
| actually power off the computer like it can today.
|
| I think the message should have said: "Windows shutdown complete.
| Please power off the computer."
|
| This more clearly implies that not only is it safe to turn off
| your computer, it's recommended you do so.
| dist-epoch wrote:
| > Please power off the computer.
|
| Sounds a bit like ordering the user, I guess that's why they
| went with the other message.
| advisedwang wrote:
| This message helps reinforce that shutting down the computer
| before seeing that message was NOT safe.
| bombcar wrote:
| Remember that it's an all-black screen that came on after a
| blue cloud screen with "Please wait while your computer shuts
| down".
| davidt84 wrote:
| 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.
| xg15 wrote:
| Semi-OT, but is there still any situation in modern computers
| where turning it off would be "unsafe"? I.e. if you yanked the
| power cord at some specific time, the system would take
| irreversible damage?
|
| Was this actually a real danger at all at some point?
|
| It's obvious that cutting the power without shutdown will lead to
| data loss of everything not written to persistent storage. But
| for old PCs, the warning was always that it could also physically
| damage the PC, e.g. damage the hard drives or something like
| that. Is this still the case?
| BugsJustFindMe wrote:
| > _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.
| dist-epoch wrote:
| Older hard-drives didn't automatically park the head on power
| loss, leaving it in a dangerous position above the platters.
| Any shock would smack it into the platters.
| SoftTalker wrote:
| My first hard drive came with a utility program to park the
| heads. Was recommended to run it before powering off
| Ekaros wrote:
| 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.
| rzzzt wrote:
| 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.
| advisedwang wrote:
| 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.
| Syonyk wrote:
| 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.
| jmholla wrote:
| > 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.
|
| I recently did this with one of my Thinkpads, doing it during
| a battery firmware update among others. I wasn't successful
| in finding such a solution though. Where have you had success
| in finding some of the more obscure repair techniques?
| jowea wrote:
| 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.
| ryandrake wrote:
| Yes, I know about disk caches and data corruption and blah blah
| blah. But to me, it's yet another condescending reminder of who's
| actually in charge of the computer (hint: It's not the user, like
| it was in the days of yore). You don't just turn off your
| computer anymore. No, that would put the user too much in
| control. Now you _request_ to the operating system: "Pretty
| please, with sugar on top, if you're not too terribly busy doing
| whatever it is you're doing, would you mind powering off?"
|
| The computer has its own agenda and agency, and increasingly the
| user's wishes are unimportant. We've been conditioned to _ask_
| the computer to do things rather than _command_ it.
| dullcrisp wrote:
| This is why I alias kill to kill -9 on all my systems.
| gapan wrote:
| 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.
| kragen wrote:
| 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.
| 1970-01-01 wrote:
| >This message was displayed when shutdown was complete and the
| computer did not support software-initiated power-off. It told
| the user, "Okay, shutdown is complete. It's okay. You can hit the
| power button now. I won't get mad; I promise."
|
| That's a somewhat unsatisfactory answer, or more of a software-
| minded answer. The full answer: Because ATX power was a NEW
| thing. AT motherboards and power supplies were overwhelmingly
| still in-use.
|
| https://en.wikipedia.org/wiki/PS-ON_Signal
| Joker_vD wrote:
| > 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.
| 1970-01-01 wrote:
| PS-ON and ACPI states are different things. You could fully
| shutdown an ATX system without ACPI 1.0
|
| https://electronics.stackexchange.com/questions/204205/what-.
| ..
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