[1] It allowed users to run DOS software for the IBM PC by clipping a unit onto the chassis of the Macintosh 128K, and included a keyboard extender to provide the function keys and numeric keypad that are absent from Apple's original keyboard.

The name refers to an IBM PC advertising campaign of the time featuring Charlie Chaplin's "Little Tramp" character.

While running DOS software using MacCharlie, users could still access the Macintosh menu bar and desk accessories.

However, the DOS environment, which ran in a window, was text-only and did not permit Macintosh applications to run concurrently while in use.

[2] This slowness, coupled with the declining prices of real IBM PC compatibles, contributed to the short market life of the MacCharlie.