The Atari ST was one of multiple home computers of the 1980s that came out with the Motorola 68000 CPU. While very capable indeed it lacked compatibility with the ubiquitous IBM PCs and PC clones of the era. The Atari ST already supported the FAT file system, so you could read and write regular PC floppy disks, but running MS DOS or MS DOS programs was a costly and slow process on the 68k CPU. So a German company by the name of Sack Electronic GmbH invented the PC Speed Emulator. A hardware assisted piece of kit that would solder directly onto the top of the Motorola CPU!