Floppy disks store data that can be read and written by disk drives. An ordinary floppy disk (initially called a “blank floppy”) starts out empty and can be used to save and load data or programs. The other two types of disks, the FORTH Boot Disk and the Extended FORTH Boot Disk, are read-only (their contents cannot be modified by a disk drive), and they contain two variants of Eloraam’s FORTH interpreter that ships with RedPower Control. The Extended FORTH Boot Disk contains more built-in words than the normal FORTH Boot Disk (such as words for controlling sortrons), but requires at least one 8 kB RAM module to be installed as the computer’s built-in memory is not large enough to load and run the larger operating system.