A pocket computer was a small calculator-sized handheld programmable computer.This specific category of computers existed primarily in the 1980s. Manufacturers included Casio, Hewlett-Packard, Sharp, Tandy/Radio Shack (Selling Casio and Sharp models under their own TRS line) and many more.The programming language was usually BASIC, but some devices offered alternatives. For example the Casio PB-2000 could be programmed in Assembly, BASIC, C, and Lisp.