What a strange computer ! It was built by IBM (like the Atari Jaguar few years later) in Japan for Sega, and was sold only there.
It is an IBM PC AT compatible system mixed with a Sega Megadrive (Genesis) console. On the front panel, one can find a Megadrive cartridge slot, two joystick connectors, a reset button, a MD/PC switch, a volume slider, a headphone output, a power button, keyboard/mouse connectors (PS/2) and one 3.5'' disk drive.
Three models were released, a low-end Model 1, with 640k RAM and no HD, a Model 2 with two floppies and no HD and 1MB RAM, and the high-end Model 3, with one floppy, 2.5MB RAM and a 30MB drive. All three shipped with the same software and accessories.
Amstrad made later a similar computer called MegaPC.
Full-stroke professional keyboard. 106 keys with function keys, cursor keys and numeric keypad