The Atari Portfolio (Atari PC Folio) is an IBM PC-compatible palmtop PC, released by Atari Corporation in June 1989. It is the world's first palmtop computer.

In 1989 DIP Research Ltd. developed the DIP Pocket PC. DIP licensed this product to Atari for sale as the Portfolio in the UK and the US. In Spain and Germany the computer was marketed as the PC Folio. DIP stood for Distributed Information Processing but it is also rumored that it stands for David, Ian and Peter the three founding members of the DIP company.

The Portfolio is based on the Intel 8088 architecture and uses a 80C88 CPU clocking in at slightly under 5MHz. The machine runs the DIP DOS operating system which is largely compatible with MS-DOS 2.11. The machine has 128KByte of RAM, and 256KByte ROM that has the OS and some applications built in. The RAM is divided between system memory and local storage (the "C: drive"). An LCD monochrome display provides 240x64 pixesls, or 40x8 characters of text. The display has no back-light. Sound is provided by a small dual tone multi frequency speaker that can simulate telephone tones so users could dial phone numbers by holding the hand-set of a telephone to the speaker.

The Portfolio uses three AA size removable alkaline batteries and memory is preserved during battery changes. This allowed a user to carry additional batteries for extended use. A power supply unit was also available for charging and running the machine.

Various accessories were created for the machine, such as memory expansions, serial and parallel interfaces, memory cards, PC Card drive, and more. ROM would be upgraded resulting in various versions of the Portfolio with different ROM versions.

The Intel 8088 microprocessor is a variant of the Intel 8086. The 8088 has an 8-bit external bus instead of the 16-bit bus that the 8086 has. The 16-bit registers and the 1MByte address range are unchanged, however. The 8086 and the 8088 have the same execution unit (EU), only the Bus Interface Unit (BIU) differs.

The original IBM PC architecture is based on the Intel 8088. The CPU runs at 5 to 16 MHz, has a 20-bit address bus and can work together with the 8087 Co-Processor. The 8088 was launched in 1979. The 8088 is compatible with the Intel 8085.