Two T10 Torx screws hold the hard drive in place.

Once they're removed, the hard drive easily pivots up and out of the system.

There isn't really room in here for a second drive, but you could certainly swap this one out yourself. You could hypothetically install an SSD, but this seems like such a good a media computer that it would be a shame to limit it to current SSD capacities.

This + that = easy Time Machine internal backup!