I carry a 2 TB Silicon Power drive on a keychain sometimes.
In addition to an encrypted partition for secure data transport, I keep a fat32 partition that can supplement phone media when I travel.
A few file formatting choices (mp3 or mp4 suffixes) mean that media playback usually works with tvs that I trust, too.
If I need more space, I can temporarily delete a few albums. No big deal.
Haha! My definitions are arbitrary now that I think about it. Tons of gray area, since it's all fiction to begin with.
My definition of 'soft' would be any magic system that lacks exact rules or a concrete cause and effect relationship with scale. Flexible power from a vague connection to a god, planet of origin, or elemental source would be soft. Even softer if there are dozens or hundreds of vague sources with unpredictable effects.
Specific, quantifiable effects from a concrete source (a specific spell, ritual, or x amount of a substance) would be hard.