Comment by yumraj

4 years ago

This sounds like laptops are fine, but iMacs and Minis are effed.

Curious, what's the real world risk of full OS level corruption and not just data loss?

21 comments

yumraj

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marcan_42  4 years ago

Good question. I just started up a loop doing USB-PD hard reboots on my MBA every 18 seconds (that's about one second into the desktop with autologin on, where it should still be doing stuff in the background). Let's see if it eats itself.

CrLf  4 years ago

Laptops are fine unless your battery has issues and you get occasional power losses, which seems to be not too uncommon for third-party batteries (which themselves are not too uncommon since Apple will charge you an arm and a leg to replace half your laptop if you have a defective battery).

  • marcan_42  4 years ago

    Bad batteries generally allow for last-gasp handling, and I've definitely seen the SMC throw a fit on some properties a few seconds before shutdown due to the battery being really dead. Not sure if macOS handles this properly, but I'd hope it does, and if it doesn't they could certainly add the feature. It would be quite an extreme case to have a battery failure be so sudden the voltage doesn't drop slowly enough to invoke this.

    • chrismorgan  4 years ago

      A fair fraction of the bad batteries I have seen have not behaved like this. Things like immediate power failure on disconnecting AC power, or claiming to be at 30% and then dying, or denying the existence of the battery altogether (two of these have happened to me personally—one at the ripe age of four months rather than due to age—and three or four to other family members). It’s certainly more common for them to just fade fairly rapidly to zero and die there, but it’s by no means rare for them to spontaneously fall over.

      4 replies →

    • joshspankit  4 years ago

      iOS doesn’t. A bad battery makes it think it has more time than it does, and cleanup tasks can get killed just as they start.

coldcode  4 years ago

Does anyone here run a desktop Mac without a battery backup device?

All of my Macs are either laptops or have a hardware backup device, so unlikely a write would be lost due to power failure (unless backup device failed which could happen).

  • wila  4 years ago

    Sure.. last power failure was like 4 years ago and the one before that was also measured in multiple years.

    Back when I still used a UPS down here, it was usually the UPS that died and triggered the power failure. So I stopped investing in a UPS.

    • joshspankit  4 years ago

      Where I live the power is quite dirty, so even when power losses are measured in years I invest in line-filtering UPS’ to extend the life of my systems.

      I even lost a MBP to a light flickering event with 0 power loss. Fried the charging circuit straight through the original power brick.

winter_blue  4 years ago

Wait, why are iMacs and Minis affected more? (I read the twitter thread; I'm not seeing why.)

  • Gaelan  4 years ago

    Laptops have batteries, so an AC power failure doesn't mean they immediately crash: they just keep running on battery until the battery gets low, at which point the system cleanly hibernates.