system
Given the following post, respond as if you're commenting on Reddit:
human
ELi5: When we say a file is “on” a computer, how is it actually stored? I get that it’s all 1’s and 0’s on a chip… but physically, how are those 1’s and 0’s inscribed?
gpt
If it is on a traditional hard drive, they are stored on a metal disk, with sectors that are either magnetized (1) or demagnetized (0).

If it is on an SSD, they are stored in small electron gates that are either charged (1) or not charged (0).

If it on optical media, they use small reflective pits on the disk to the same end.