Programmable calculator to use magnetic strips were the HP-41C and TI-59. Continuous memory does not lose its content when the calculator is switched off. With continuous memory the user can, for example, change batteries without losing the entered programs. Compact Cassettes offered a simple, inexpensive alternative to magnetic cards. Usually, an interface module, such as the Casio FA-1, was used to connect the calculator to an ordinary cassette recorder and digital data were encoded as frequency-shift keyed audio signals. Sharp and Hewlett-Packard also sold dedicated micro- or mini-cassette recorders that connected directly to the calculator. These set-ups, while being more practical and
History of science and technology in Japan desktop calculator. The Sharp QT-8D, a desktop calculator released in 1969, was the first calculator to have its logic circuitry entirely implemented with LSI ("large-scale integration") integrated circuits (ICs) based on MOS ("metal-oxide-semiconductor") technology. Upon its introduction, it was one of the smallest electronic calculators ever produced commercially. The first portable calculators appeared in Japan in 1970, and were soon marketed around the world. These included the Sanyo ICC-0081 "Mini Calculator", the Canon Pocketronic, and the Sharp QT-8B "micro Compet". In January 1971, the Sharp EL-8 was close to being a pocket calculator, weighing about one pound, with a vacuum