Support decimal output

[florensie]

Because it's faster, I thought I would use terabytes as input for the disk sizes, but in some situations that doesn't work correctly:

The total usable space should be 18.5 TB here, with no unused space.

[darkling]

I'm afraid that doesn't really work. It kind of relies on "1" being 1 GiB, because that's the unit of allocation of the FS. It's definitely a good idea to clarify that by putting a "GiB" label on the values, though.

[Forza-tng]

I'm afraid that doesn't really work. It kind of relies on "1" being 1 GiB, because that's the unit of allocation of the FS. It's definitely a good idea to clarify that by putting a "GiB" label on the values, though.

Perhaps allow for TiB units as input, but convert to GiB for the internal logic? I too find it easier to work with TiB units. Of course, we should not restrict to TiB.