Re: Shutdown - 25 Years Later

On 4/22/25 12:13, The Natural Philosopher wrote:

On 22/04/2025 10:27, Carlos E.R. wrote:

On 2025-04-22 11:03, The Natural Philosopher wrote:

On 22/04/2025 09:35, Carlos E.R. wrote:

On 2025-04-21 02:29, Lawrence D'Oliveiro wrote:

On 21 Apr 2025 08:24:22 +1000, Computer Nerd Kev wrote:
>

It sounds like they're talking about the cache in the drive itself,
making sure data is physically written out before power-off.

>
Unfortunately, you could be right.
>
I say “unfortunately“, because I think it’s a dumb idea for drives to have
their own cache.

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Not at all. There is a huge speed improvement.
>

The key is to have a large enough capacitor in the drive to flush all those caches on power off.

>
Or power off by command, not pulling the cable.
>

The reason you pull the cable is
 (i) the electricity company did it for you
(ii) the power off button/command didn't work.
(iii) There was no swap left and you couldn't even log in to issue the shutdown command
 

My Orange Pi 5 freezes all the time. I don't know if the power off button is any better than pulling the power cable.
One thing I have been pondering, is a hardware heartbeat. I vaguely remember reading that such a thing exists. I wondered if it was possible to hang a clean-up routine off it. i.e if something stops the heartbeat try to flush writes to disk, before the power reset. It is probably a stupid idea, because by the time the computer was frozen enough to prevent the heartbeat, it is probably too sick to run any clean-up code, and/or the pending disk writes may still leave the disk in an inconsistent state.