Machine for performing arithmetic operations and certain mathematical functions automatically. Blaise Pascal devised a digital arithmetic machine in 1642. By the late 19th century, such machines had become smaller and easier to use, and desktop machines appeared in the early 20th century. Electronic data-processing systems in the mid-1950s led to the obsolescence of mechanical calculators. Miniature solid-state devices ushered in calculators that could perform mathematical functions in addition to basic arithmetic, and also store data and instructions in memory registers, providing programming capabilities similar to those of small computers.