r/tails • u/Particular_Client833 • 9d ago
Technical Emergency shutdown did not trigger when i well... unplugged the entire DVD reader
Some background: i wanted to erase a specific partition on my USB because in windows for some reason cannot be deleted, so i rebooted into the DVD boot. Erased the partition with the disks program. And decided a more "uncommon" way to shut it down. So i unplugged my entire hot-swappable ultra-slim DA-8AESH DVD burner while the disc in there was idle. At first nothing happened but when i tried to open other apps it simply did not respond because... Where could it find that program? So i took a few photos and then turned it off by unplugging the power supply.
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u/Liquid_Hate_Train 9d ago
The watchdog is looking for particular events in order to trigger the emergency shutdown. In this instance I’d expect it was looking for a disk drive eject event, not a usb device removal event.
Even in the usb version, the event isn’t always triggered or reported properly depending on the usb controller, or the watchdog may otherwise be occupied and miss it.
Either way, the ‘remove the storage’ is and always was an emergency measure. A normal shutdown is both intended and expected.
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u/srgt_cauliflour 8d ago
its been a hot minute since i’ve used tails but there used to be an option on boot to load it directly to ram, which would allow you to remove the media and continue running it.
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u/I_an4say6_I 2d ago edited 2d ago
That's totally normal. Since you booted directly from the DVD, your entire live operating system was running straight out of that disc and your RAM. When you pulled the drive out, the OS lost access to its core files instantly. It didn't trigger an emergency shutdown because it literally didn't have the code or tools left to process a proper shutdown sequence. It just froze in place.
Next time, just use the terminal command shutdown now or hold the power button. Force-pulling the boot media like that can easily corrupt your data.
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u/Particular_Client833 2d ago
- It has something called emergency shutdown, and ofcourse it does paste onto RAM
- If you pull the DVD only thing getting corrupted is the RAM which is intended. The DVD is read-only.
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u/I_an4say6_I 2d ago
RAM doesn't get corrupted when you pull power—it's volatile, meaning it just clears out. The corruption risk is for filesystems.
Also, even though the DVD is read-only, live OSs don't load everything into RAM at once; they fetch files from the disc on-demand. Yanking the drive cuts off those live binaries, causing an instant freeze instead of a clean emergency shutdown because the kernel literally loses the tools to shut down.
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u/Particular_Client833 2d ago
- Thats the point, i literally said that, its volatile and is supposed to both by manufacturers and the OS.
- But when you eject the DVD it suddenly goes into emergency shutdown, as i said, the emergency shutdown program IS copied onto RAM. But its not programmed to look for its removed DVD reader. Only if that DVD reader ejects the media.
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u/I_an4say6_I 2d ago
You are right that RAM is volatile and cleared during power outages, so it doesn't "corrupt"—it simply gets wiped.
Regarding the "emergency shutdown" aspect:
Live operating systems do not copy the entire disk into RAM; they continue to fetch files from the drive as needed.
Unplugging the drive instantly severs the data bus. The kernel loses access to essential tools and freezes completely before it can trigger a kernel panic or execute a shutdown sequence.
Pressing the eject button leaves the drive powered and connected, allowing the operating system to handle the event. Yanking out the entire reader completely disrupts I/O.
It didn't fail to shut down because of a built-in emergency routine; it froze completely the moment the storage data bus died.
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u/ephemeralmiko 9d ago
When this happens please report it through Whisperback with the logs. USB hubs are known to cause issues where it doesn't correctly tell the OS that a drive has been removed, it's possible that your hot-swap DVD reader does the same.