Open up Disk Utility, which can be found in the Applications folder, under Utilities. Alternately, use the search function in Finder to search "This Mac" for Disk Utility.

Tucked away in the Utilities folder, Disk Utility and its First Aid feature can be used to check if a disk is damaged and repair it, create a disk image, partition a disk, and so much more ...

Need to store 500 terabytes and have it last a very, very long time? One scientist has been experimenting with laser etchings on glass.