The HP 200LX (also known as Project Felix) is a personal digital assistant introduced by Hewlett-Packard in 1994. It was often called a palmtop computer, and it was notable that it was, with some minor exceptions, a MS-DOS-compatible computer in a palmtop format, complete with a monochrome graphic display, QWERTY keyboard, serial port, and PCMCIA expansion slot.
Read more about HP 200LX: Description, Current Usage, Japan, Common Problems, Exceptions To 100% DOS Compatibility, Other Notes, Easter Eggs