>>11684164It will weigh more when data is written to it because data is written to hard drives by magnetizing tiny sections of the platter, which is adds energy and as we all know e=mc2. You would need an extremely sensitive scale to measure the difference though.
Generally you would assume a magnetized section = 1 and unmagnetized = 0, so all 1s would be heavier than all 0s. Tecnically it could be designed to interpret a magnetized section as a 0 though, sort of like if you installed all your light switches upside down so the off/on labels sere swapped.
