DThe Atari Portfolio (Atari PC Folio) is an IBM PC-compatible palmtop PC, released by Atari Corporation in June 1989. This makes it the world's first palmtop computer.
The Portfolio uses an Intel 80C88 CPU running at 4.9152 MHz and runs "DIP Operating System 2.11" (DIP DOS), an operating system mostly compatible to MS-DOS 2.11, but with some DOS 2.xx functionality lacking and some internal data structures more compatible with DOS 3.xx. It has 128 KB of RAM and 256 KB of ROM which contains the OS and built-in applications. The on-board RAM is divided between system memory and local storage (the C: drive). The LCD is monochrome without backlight and has 240×64 pixels or 40 characters × 8 lines.
Power is supplied by three AA size removable alkaline batteries. The computer's memory is preserved during battery changes. There is also an optional AC adapter (110 V: HPC-401, 220 V: HPC-402).