(If it’s an SSD you are after, read Best external SSD for Mac.) There are plenty of choices, too, with compact, portable hard drives designed for use with laptops, and desktop drives with larger ...

How big is 20 terabytes? Enough to hold roughly 10 million photos or 10,000 hours of HD video. So, very possibly an entire lifetime of photos, home videos, and other files can be safely backed up to ...