Masatoshi Shima

is a Japanese electronics engineer. He was one of the architects of the world's first microprocessor, the Intel 4004. In 1968, Shima worked for Busicom in Japan, and did the logic design for a specialized CPU to be translated into three-chip custom chips. In 1969, he worked with Intel's Ted Hoff and Stanley Mazor to reduce the three-chip Busicom proposal into a one-chip architecture. In 1970, that architecture was transformed into a silicon chip, the Intel 4004, by Federico Faggin, with Shima's assistance in logic design.

Early life and career He studied organic chemistry at Tohoku University in Sendai, Miyagi Prefecture, Japan. With poor prospects for employment in the field of chemistry, he went to work for Busicom, a business calculator manufacturer, joining in Spring 1967. There, he learned about software and digital logic design, from 1967 to 1968. a chipset for the Busicom 141-PF calculator that led to creating the first microprocessor, the Intel 4004. In April 1968, Shima was asked to design the logic for what was intended to become a future chipset to be designed and produced by a semiconductor company.

Intel 8080 to Zilog Z8000 After the 4004, Intel designed the 8008 (architecture by Computer Terminal Corporation, design by Federico Faggin and Hal Feeney). Shima then joined Intel in 1972. developed the transistor-level and physical implementation of the Zilog Z80, under the supervision of Faggin, who conceived and designed the Z80 architecture to be an instruction set compatible with the Intel 8080. This was followed by the same task for the 16-bit Z8000.

According to coworkers from Intel, Faggin's method that Shima used was to design all logic at the transistor level, directly and manually, not at the gate and/or register level. The schematics were thus hard to read, but as transistors were drawn in such a way that they suggested a "floorplan" of the chip, it helped when making the physical chip layout. However, according to Shima, the logic was first tested on breadboards using transistor–transistor logic (TTL) chips, before being manually translated into MOS transistor equivalents.

After returning to Japan, Shima founded the Intel Japan Design Center in 1980, and VM Technology Corporation in 1986. At VM, he developed the 16-bit microprocessor VM860 and 32-bit microprocessor VM 8600 for the Japanese word processor market. He became a professor at the University of Aizu in 2000.