A 75/25 mix. What is your answer for that?
No idea
but I love dredging info from my ravaged brain so I'll throw some proverbial at the wall.
Without searching the web, because that's cheating.
Data is stored on magnetic media - be that tape or disc - as discrete magnetic fields. As magnetism is energy and energy is mass, a magnetised bit of data on magnetic medium MUST be heavier than just the medium itself, and there must be way to theoretically measure it. I guarantee you 100% that someone will have done the maths and worked out how much energy a bit has for a given data density and a given field strength.
From the elementary comp.sci I learned oh my god 25 years ago, 0 on magnetic medium isn't represented by the lack of a magnetic field, it's a magnetic field in the opposite direction. If it's the same strength field a 0 will have the same energy as a 1, so the total energy in the disk would stay the same.
Back when I learned this stuff, floppy disks were split into radial sectors and tracks, like a dartboard, and hard drives were basically a stack of discs (called platters) on top of each other, using a sturdier material that could pack more data onto the surfaces.
If the track and sector approach still holds then it means that the data density can't be uniform across the whole disk. The further outer along the disc you go the less dense the data is in order for track and sector addressing to make any kind of sense. With variable data density the "weight" of any given bit depends upon where on a disk it is.
And if it's on a platter higher up in the rack, it means it has more potential energy because of gravity.
So my answer is, I haven't the foggiest. Any split makes it impossible to answer. I'm going to have the play the following card:
