Casio (1s, 10s, 100s, etc ... ) had nine keys. Another distinguishing innovation was the use of a single display window instead of the three display windows (one for each argument and one for the answer) used in other calculators. Casio Computer Co., Ltd. was formed in June 1957. That year, Casio released the Model 14-A, sold for 485,000 yen, the world's first all-electric compact calculator, which was based on relay technology. In the 1980s, its budget electronic instruments and its line of affordable home electronic musical keyboard instruments became popular. The company also became well known for the wide variety
Calculator stored program machine which could read and write magnetic cards and displayed results on its built-in printer. Memory, implemented by an acoustic delay line, could be partitioned between program steps, constants, and data registers. Programming allowed conditional testing and programs could also be overlaid by reading from magnetic cards. It is regarded as the first personal computer produced by a company (that is, a desktop electronic calculating machine programmable by non-specialists for personal use). The Olivetti Programma 101 won many industrial design awards. Another calculator introduced in 1965 was Bulgaria's ELKA 6521, developed by the Central Institute for Calculation Technologies