How do you save your hard disk and other data storage devices from solar flare?

Answer 1

Your personal hard disc and other data storage devices are already protected quite well from solar flares, because they are on the surface of the Earth. The Earth protects them in two major ways: the protective blanket of atmosphere which protects against the passage of most energetic particles, and the Earth's magnetic field (the "magnetosphere") which deflects many energetic particles which carry an electrical charge. In addition, your hard disc is protected by the computer chassis and its own metal & plastic casing.

If you want more perfect protection, take your hard disc down into a deep mine far below the Earth's surface. It is even more difficult for energetic particles to penetrate the ground than the atmosphere, since solids are much denser than gasses. If you aren't willing to do that, you could cover it with some dense material, such as a cover made of iron or lead or thick concrete.