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 fluorescent display (VFD) and rechargeable NiCad batteries. The EL-8 was the first battery-powered handheld calculator. The concept of a single-chip calculator was conceived by Sharp engineer Tadashi Sasaki in 1968. The first truly pocket-sized electronic calculator was the Busicom LE-120A "HANDY", the first single-chip calculator to be built, released in February 1971. The Busicom 141-PF desktop calculator, released in March 1971, was the first computing machine to use a microprocessor, the 4-bit Intel 4004 (co-designed by Busicom's Masatoshi Shima). In 1971, Tadashi Sasaki began research on the use of LCD displays for calculators at Sharp Corporation. In 1973, Sharp commercially