The Casio PB-1000 was a handheld computer released by Casio in 1987. Revolutionary for its time, it featured a touchscreen display which consisted of 16 keys built into the screen, arranged in fixed positions on a four by four matrix.The computer itself included 8Kb of RAM and it was possible to install a 32Kb memory expansion card.The PB-1000 was programmable in both a custom version of the BASIC language and assembly language.