Occasionally, when I am using Pacman, it will just freeze right in the middle of an operation; then it has to be terminated and the operation must be restarted. I can't explain why this happens.
Then, I actually have the entire OS freeze (completely separate occasion, not related to the Pacman problem, though they are alike in nature). No buttons register, X freezes, logs aren't written too, nothing. Nada.
As a very rough observation, this seems to happen when the lappy is moved a lot. I can't say that's it though.
This is very disconcerting; I'm just glad ext4 has been very kind about it so far, as when this happens I have to hard reboot the system by pressing the power button for like 10 seconds, because nothing else works.
I've checked my logs, and nothing seems to be abnormal.