When the computer wants a bit to be a 1, it pops it down. When it wants it to be a 0, it pops it up.
If it were like a punch card, it couldn’t be rewritten as writing to it would permanently damage the disc. A CD-RW is basically a microscopic punch card though, because the laser actually burns away material to write the data to the CD.
Current ones also store multiple charge levels per cell, so they’re no longer one bit each. They have multiple levels of “punch” for what used to just be one bit.
More like microscopic fidget bubble poppers.
When the computer wants a bit to be a 1, it pops it down. When it wants it to be a 0, it pops it up.
If it were like a punch card, it couldn’t be rewritten as writing to it would permanently damage the disc. A CD-RW is basically a microscopic punch card though, because the laser actually burns away material to write the data to the CD.
They work through electron tunneling through a semiconductor, so something does go through them like an old punch card reader
Current ones also store multiple charge levels per cell, so they’re no longer one bit each. They have multiple levels of “punch” for what used to just be one bit.