Of course, if you're trying to use modern hard drive material to fill the observable universe, you'll reach black-hole density in no time flat (if I recall corr

Of course, if you're trying to use modern hard drive material to fill the observable universe, you'll reach black-hole density in no time flat (if I recall correctly, a Solar System-sized black hole has a density similar to the Earth's atmosphere.) And even if you're not using modern technology to fill the space, there is a quantum limit on the minimum amount of energy required to represent one bit. Interestingly, a black hole's entropy is proportional the surface area of its event horizon, so the maximum information capacity of a given region of space is too. (See also: holographic universe.)