5 ms·
High-end laptops like ThinkPads often have an accelerometer, I'm not quite sure how hard it would be to access it from GRUB2 but it would definitely be a neat t
by lorenzhs 11y ago
High-end laptops like ThinkPads often have an accelerometer, I'm not quite sure how hard it would be to access it from GRUB2 but it would definitely be a neat trick to boot a hidden partition or something. Or maybe display a fake error message and refuse to boot if it's not sideways as a crude method of protection.
- agumonkey 11y agoOh I remember someone managing to tap into that ! gosh ... I hope I can find it again. ps: #ibmthinkpad refreshed my memory. > old thinkpads (<= T60/61 or something): hdaps.ko from the kernel > newer thinkpads (up to X201/T400/T410?) hdaps.ko from tp-smapi > new thinkpads: no wai (simply because no linux driver as of now, nobody reversed the windows driver yet)
- JoshTriplett 11y agoCurrent Thinkpads don't necessarily have the accelerometer anymore, because they don't have spinning drives. ("hdaps" referred to "hard drive active protection system".)
- dfox 11y agoIIRC, even old(-ish) X200/X201 does not necessarily have accelerometer if it was factory configured with SSD.
- lorenzhs 11y agoThe T450's Hardware Maintenance Manual reads The system board has an accelerometer, which can be broken when several thousands of G-forces are applied. Note: Dropping a system board from a height of as little as 6 inches so that it falls flat onto a hard bench can subject the accelerometer to as much as 6000 G's of shock. so it seems like at least some current ThinkPads still come with an accelerometer, and it's not in the disk.
- agumonkey 11y ago450 series are never sold with mechanical hdds ? Do they use it to report misuse ?
- eli 11y agoOld MacBooks too https://www.youtube.com/watch?v=6uvQTTPr9Rw https://www.youtube.com/watch?v=6uvQTTPr9Rw
- jsingleton 11y agoMany laptops have these sensors, often as part of a hard drive protection system. If it detects 9.8g suddenly going to 0g then it parks the read head as it's probably just been dropped. I'm not sure if they're still present in this era of SSDs. Maybe if they weren't part of the disk itself. They were used by the Quake-Catcher Network project from Stanford. Although from the OS. ...seismic network by utilizing sensors in and attached to internet-connected computers. https://github.com/carlgt1/qcn https://github.com/carlgt1/qcn Edit: Yes, I meant ms⁻² not g. Been a while since I've done any physics. 9.8g is probably more like what it would sense when hitting the floor, which is a bit too late to do anything useful. At least I didn't claim it to be 6.54×10⁻¹⁰ Nm²kg⁻² (bonus points if you get this).
- delazeur 11y ago> If it detects 9.8g suddenly going to 0g then it parks the read head as it's probably just been dropped. 9.8g? Is your office inside a centrifuge? :-P
- dikaiosune 11y agoMaybe supposed to be 9.8 m/s^2 ?
- yoha 11y agoTo clarify what delazeur meant: g already means "9.8 m/s²" Thus, normal gravity is 1g and free fall is 0g. 9.8g would mean 9.8 times the gravity at Earth surface, that is "96 m/s²". You would feel almost ten times as heavy. For reference: Jupiter "surface" gravity is 25.9 m/s² Sun "surface" gravity is 274 m/s²
- yompers888 11y agoAssuming force being applied along the axis of the spine, and that it continues, you would experience tunnel vision, lightheadedness, loss of consciousness, and eventual death. People can't really handle more than 5g on that axis without a special g suit. Lesson: Don't try to take it standing up.
- sschueller 11y agoShake laptop to boot Linux :)
- dheera 11y agoI've been wanting to get access to the ThinkPad accelerometer in Linux but haven't yet found a way to do so.
- bcg1 11y agoCould even consider implementing this inside a coreboot payload to load a "hidden" OS that on the BIOS flash chip. https://www.coreboot.org/Linux https://www.coreboot.org/Linux