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5 ways to reboot a PC. None of them reliable.

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Re: 5 ways to reboot a PC. None of them reliable.

#31

Post by kelnos »

notYoursAtAll wrote: post #29
yuhong wrote: post #19

Earlier quoted context omitted.

Power off uses APM or ACPI and is not related.

"How to shut down a PC" no mention of Linux, but apparently that is the topic. But since it's not mentioned in the topic, it's going to come up. Personally I use a batch file and SysInternals to shutdown (after forcing bad-behavior apps to exit). Sounds like you need a SysInternals for Linux??

The software that you use on top of your OS to ask your OS to reboot is irrelevant. We're talking about what the OS has to do to the hardware to get it to reboot. The blog post even notes that Linux 3.0 will be attempting to mimic the kludgey way in which Windows tries to get your machine to reboot.

Re: 5 ways to reboot a PC. None of them reliable.

#32

Post by kronusaturn »

BrandonM wrote: post #16

I don't know if anyone else remembers, but I think it was either Windows 95 or Windows 98 which, after selecting shut down, the eventual result would be a message that said, "It is now safe to turn off your computer." I remember thinking it was magic when the computer would actually turn itself off at this point. This article provides a good explanation for why that behavior was necessary.

No, that was a completely different issue. Before ATX the power supply could not be controlled by software at all—it only had a mechanical switch, often near the back of the machine rather than in front, because that's where the power supply was.

This article is about rebooting, as in resetting all the hardware without turning off the power. The original IBM PC had a well defined way to do this, but after decades of clones and clones of clones there's no longer any one method that's guaranteed to work on any machine.

Re: 5 ways to reboot a PC. None of them reliable.

#33

Post by yuhong »

Tuna-Fish wrote: post #30
rbanffy wrote: post #25

Earlier quoted context omitted.

Isn't that kludgy? I mean, using a keyboard controller (in effect, a second computer) to reset the one you can't?

The reason was that IBM bought the rest of the chips "as they were" from Intel, so all the logic that they made themselves ended in the in-house keyboard controller. x86 had an external interrupt line for reset, and an io pin in the keyboard controller was tied to this. That was a reasonable way to get true hard reset back then.

And what I meant by related was that another pin in the same keyboard controller was tied to the A20 gate, so it was toggled in a similar way.
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