Masatoshi Shima

Last updated
Masatoshi Shima
Masatoshi Shima.jpg
Masatoshi Shima at the Computer History Museum 2009 Fellow Awards event
Native name
Born (1943-08-22) August 22, 1943 (age 76)
Shizuoka, Japan
Alma mater Tohoku University (B.S., 1967)
Tsukuba University (Dr.Eng., 1991)
Known for Microprocessors: Intel 4004, 8080, Zilog Z80, Z8000
Peripheral chips: Intel 8259, 8255, 8253, 8257, 8251
Awards Kyoto Prize (1997)
Computer History Museum Fellow (2009) [1]
Scientific career
Fields Electrical engineering
Institutions Busicom (1967-1972)
Intel (1972-1975)
Zilog (1975-1980) [2]
University of Aizu (2000)

Masatoshi Shima(嶋 正利,Shima Masatoshi, born August 22, 1943, Shizuoka) is a Japanese electronics engineer. He was one of the designers of the world's first microprocessor, the Intel 4004, producing the initial three-chip CPU design at Busicom in 1968, before working with Intel's Ted Hoff, Stanley Mazor and Federico Faggin on the final single-chip CPU design from 1969 to 1970. [3] [4] [5]

Microprocessor Computer processor contained on an integrated-circuit chip

A microprocessor is a computer processor that incorporates the functions of a central processing unit on a single integrated circuit (IC), or at most a few integrated circuits. The microprocessor is a multipurpose, clock driven, register based, digital integrated circuit that accepts binary data as input, processes it according to instructions stored in its memory and provides results as output. Microprocessors contain both combinational logic and sequential digital logic. Microprocessors operate on numbers and symbols represented in the binary number system.

Intel 4004 4-bit central processing unit

The Intel 4004 is a 4-bit central processing unit (CPU) released by Intel Corporation in 1971. It was the first commercially available microprocessor, and the first in a long line of Intel CPUs. The chip design, implemented with the MOS silicon gate technology, started in April 1970, and was created by Federico Faggin who led the project from beginning to completion in 1971. Marcian Hoff formulated and led the architectural proposal in 1969, and Masatoshi Shima contributed to the architecture and later to the logic design. The first commercial sale of the fully operational 4004 occurred in March 1971 to Busicom Corp. of Japan for its 141-PF electronic calculator, for which it was originally designed and built as a custom chip.

Busicom company

Busicom was a Japanese company that owned the rights to Intel's first microprocessor, the Intel 4004, which they created in partnership with Intel in 1970.


He later joined Intel in 1972. There, he worked with Faggin to develop the Intel 8080, released in 1974. Shima then developed a number of Intel peripheral chips, some used in the IBM PC, such as the 8259 interrupt controller, 8255 parallel port chip, 8253 timer chip, 8257 DMA chip and 8251 serial communication USART chip. He then joined Zilog, where he worked with Faggin to develop the Zilog Z80 (1976) and Z8000 (1979). [2]

Intel 8080 8-bit microprocessor

The Intel 8080 ("eighty-eighty") was the second 8-bit microprocessor designed and manufactured by Intel and was released in April 1974. It is an extended and enhanced variant of the earlier 8008 design, although without binary compatibility. The initial specified clock rate or frequency limit was 2 MHz, and with common instructions using 4, 5, 7, 10, or 11 cycles this meant that it operated at a typical speed of a few hundred thousand instructions per second. A faster variant 8080A-1 became available later with clock frequency limit up to 3.125 MHz.

Intel 8259

The Intel 8259 is a Programmable Interrupt Controller (PIC) designed for the Intel 8085 and Intel 8086 microprocessors. The initial part was 8259, a later A suffix version was upward compatible and usable with the 8086 or 8088 processor. The 8259 combines multiple interrupt input sources into a single interrupt output to the host microprocessor, extending the interrupt levels available in a system beyond the one or two levels found on the processor chip. The 8259A was the interrupt controller for the ISA bus in the original IBM PC and IBM PC AT.

Parallel port an interface for connecting peripherals to computers

A parallel port is a type of interface found on computers for connecting peripherals. The name refers to the way the data is sent; parallel ports send multiple bits of data at once, in parallel communication, as opposed to serial interfaces that send bits one at a time. To do this, parallel ports require multiple data lines in their cables and port connectors, and tend to be larger than contemporary serial ports which only require one data line.

Early life and career

He studied organic chemistry at Tohoku University in Sendai, 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. [3]

Organic chemistry subdiscipline within chemistry involving the scientific study of carbon-based compounds, hydrocarbons, and their derivatives

Organic chemistry is a subdiscipline of chemistry that studies the structure, properties and reactions of organic compounds, which contain carbon in covalent bonding. Study of structure determines their chemical composition and formula. Study of properties includes physical and chemical properties, and evaluation of chemical reactivity to understand their behavior. The study of organic reactions includes the chemical synthesis of natural products, drugs, and polymers, and study of individual organic molecules in the laboratory and via theoretical study.

Tohoku University Higher education institution in Miyagi Prefecture, Japan

Tohoku University, abbreviated to Tohokudai, located in Sendai, Miyagi in the Tōhoku Region, Japan, is a Japanese national university. It was the third Imperial University in Japan and is one of the National Seven Universities. It is considered one of the most prestigious universities in Japan, and one of the top fifty universities in the world.

Japan Island country in East Asia

Japan is an island country in East Asia. Located in the Pacific Ocean, it lies off the eastern coast of the Asian continent and stretches from the Sea of Okhotsk in the north to the East China Sea and the Philippine Sea in the south.

Intel 4004

After Busicom decided to use large-scale integration (LSI) circuits in their calculator products, they began work on what later became known as the "Busicom Project", [5] a chipset for the Busicom 141-PF calculator that led to the creation of the first microprocessor, the Intel 4004. [4] In April 1968, Shima was asked to design the chipset and software for the calculator. [3] Shima designed a special-purpose LSI chipset, along with his supervisor Tadashi Tanba, in 1968. [4] His design consisted of seven LSI chips, including a three-chip CPU. [5] Shima's initial design included arithmetic units (adders), multiplier units, registers, read-only memory, and a macro-instruction set to control a decimal computer system. [4] Busicom wanted to produce a general-purpose LSI chipset, for not only desktop calculators, but also other equipment such as a teller machine, cash register and billing machine. Shima began work on a general-purpose LSI chipset in late 1968, and Busicom then approached the American companies Mostek and Intel for manufacturing help. The job was given to Intel, who back then was more of a memory company and had facilities to manufacture the high density silicon gate MOS chip Busicom required. [3]

Calculator electronic device used to perform operations of arithmetic

An electronic calculator is typically a portable electronic device used to perform calculations, ranging from basic arithmetic to complex mathematics.

Central processing unit Central component of any computer system which executes input/output, arithmetical, and logical operations

A central processing unit (CPU), also called a central processor or main processor, is the electronic circuitry within a computer that carries out the instructions of a computer program by performing the basic arithmetic, logic, controlling, and input/output (I/O) operations specified by the instructions. The computer industry has used the term "central processing unit" at least since the early 1960s. Traditionally, the term "CPU" refers to a processor, more specifically to its processing unit and control unit (CU), distinguishing these core elements of a computer from external components such as main memory and I/O circuitry.

Arithmetic logic unit digital circuits

An arithmetic logic unit (ALU) is a combinational digital electronic circuit that performs arithmetic and bitwise operations on integer binary numbers. This is in contrast to a floating-point unit (FPU), which operates on floating point numbers. An ALU is a fundamental building block of many types of computing circuits, including the central processing unit (CPU) of computers, FPUs, and graphics processing units (GPUs). A single CPU, FPU or GPU may contain multiple ALUs.

Shima went to Intel in June 1969 to present the proposal. Due to Intel lacking logic engineers to understand the logic schematics or circuit engineers to convert them, Intel asked Shima to simplify the logic. [3] Intel wanted a single-chip CPU design, [3] influenced by Sharp's Tadashi Sasaki who had presented the concept to Intel in 1968. [6] This was then formulated by Intel's Marcian "Ted" Hoff in 1969, simplifying Shima's initial design down to four chips, including a single-chip CPU. [5] Due to Hoff's formulation lacking key details, Shima came up with his own ideas to find solutions for its implementation. They both eventually realized the 4-bit microprocessor concept, with the help of Intel's Stanley Mazor to interpret the ideas of Shima and Hoff. Shima was responsible for adding a 10-bit static shift register to make it useful as a printer's buffer and keyboard interface, many improvements in the instruction set, making the RAM organization suitable for a calculator, the memory address information transfer, the key program in an area of performance and program capacity, the functional specification, decimal computer idea, software, desktop calculator logic, real-time I/O control, and data exchange instruction between the accumulator and general purpose register. [3] The specifications of the four chips were developed over a period of a few months in 1969, between an Intel team led by Hoff and a Busicom team led by Shima. [5]

Sharp Corporation is a Japanese-Taiwanese multinational corporation that designs and manufactures electronic products, headquartered in Sakai-ku, Sakai. Since 2016 it has been a subsidiary of Taiwan-based Foxconn Group. Sharp employs more than 50,000 people worldwide. The company was founded in September 1912 in Tokyo and takes its name from one of its founder's first inventions, the Ever-Sharp mechanical pencil, which was invented by Tokuji Hayakawa in 1915.

Tadashi Sasaki was a Japanese engineer who was influential in founding Busicom, driving the development of the Intel 4004 microprocessor, and later driving Sharp into the LCD calculator market.

Marcian Hoff American electrical engineer

Marcian Edward "Ted" Hoff Jr. is one of the inventors of the microprocessor.

After Shima went back to Japan in late 1969 and then returned to Intel in early 1970, he found that no further work had been done on the 4004 since he left, and that Hoff was no longer working on the project. The project leader had become Federico Faggin, who had only joined Intel a week before Shima arrived. After explaining the project to Faggin, Shima worked with him to design the 4004 processor, with Shima responsible for the chip's logic. [3] He worked at the Intel offices for six months—from April until October 1970. His company then sold the rights to use the 4004 to Intel, with the exception of use in business calculators.

Federico Faggin Italian physicist and electrical engineer

Federico Faggin is an Italian-American physicist, engineer, inventor and entrepreneur. He is best known for designing the first commercial microprocessor, the Intel 4004. He led the 4004 (MCS-4) project and the design group during the first five years of Intel's microprocessor effort. Faggin also created, while working at Fairchild Semiconductor in 1968, the self-aligned MOS (metal-oxide-semiconductor) silicon-gate technology (SGT), which made possible MOS semiconductor memory chips, CCD image sensors, and the microprocessor. After the 4004, he led development of the Intel 8008 and 8080, using his SGT methodology for random logic chip design, which was essential to the creation of early Intel microprocessors. He was co-founder and CEO of Zilog, the first company solely dedicated to microprocessors, and led the development of the Zilog Z80 and Z8 processors. He was later the co-founder and CEO of Cygnet Technologies, and then Synaptics.

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. [2] He was employed to implement the transistor-level logic of Intel's next microprocessor, which became the Intel 8080 (conception and architecture by Federico Faggin), released in 1974. [3] Shima then developed a number of Intel peripheral chips, some used in the IBM PC, such as the 8259 interrupt controller, 8255 parallel port chip, 8253 timer chip, 8257 DMA chip and 8251 serial communication USART chip. [2] He was not involved in the creation of the Intel 8088 or 8086.

Shima moved to Zilog in 1975 and, using only a small number of assistants, [7] 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 instruction set compatible with the Intel 8080. This was followed by the same task for the 16-bit Z8000. [3]

According to co-workers 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 therefore hard to read, but as transistors were drawn in such a way that they suggested a "floorplan" of the chip, [8] it actually helped when making the physical chip layout. However, according to Shima himself, the logic was first tested on breadboards using 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. [2]



  1. Masatoshi Shima 2009 Fellow Archived 2015-10-03 at the Wayback Machine
  2. 1 2 3 4 5 Shima Masatoshi, Information Processing Society of Japan
  3. 1 2 3 4 5 6 7 8 9 10 Masatoshi Shima
  4. 1 2 3 4 Nigel Tout. "The Busicom 141-PF calculator and the Intel 4004 microprocessor" . Retrieved November 15, 2009.
  5. 1 2 3 4 5 Federico Faggin, The Making of the First Microprocessor, IEEE Solid-State Circuits Magazine, Winter 2009, IEEE Xplore
  6. Aspray, William (1994-05-25). "Oral-History: Tadashi Sasaki". Interview #211 for the Center for the History of Electrical Engineering. The Institute of Electrical and Electronics Engineers, Inc. Retrieved 2013-01-02.
  7. Zilog had a total of 11 employees at the time, but grew to more than 1000 in a very short time.
  8. Monte Dalrymple to Peter Alfke : comp.lang.vhdl
  9. CHM. "Masatoshi Shima — CHM Fellow Award Winner". Archived from the original on October 3, 2015. Retrieved March 30, 2015.

Related Research Articles

Motorola 6800 8-bit microprocessor

The 6800 is an 8-bit microprocessor designed and first manufactured by Motorola in 1974. The MC6800 microprocessor was part of the M6800 Microcomputer System that also included serial and parallel interface ICs, RAM, ROM and other support chips. A significant design feature was that the M6800 family of ICs required only a single five-volt power supply at a time when most other microprocessors required three voltages. The M6800 Microcomputer System was announced in March 1974 and was in full production by the end of that year.

Zilog Z80 8-bit microprocessor

The Z80 is an 8-bit microprocessor introduced by Zilog as the startup company's first product. The Z80 was conceived by Federico Faggin in late 1974 and developed by him and his 11 employees starting in early 1975. The first working samples were delivered in March 1976, and it was officially introduced on the market in July 1976. With the revenue from the Z80, the company built its own chip factories and grew to over a thousand employees over the following two years.

Zilog American manufacturer

Zilog, Inc. is an American manufacturer of 8-bit and 16-bit microcontrollers. Its most famous product is the Z80 series of 8-bit microprocessors that were compatible with the Intel 8080 but significantly cheaper. The Z80 was widely used during the 1980s in many popular home computers such as the TRS-80 and the ZX Spectrum, as well as arcade games such as Pac-Man. The company also made 16- and 32-bit processors, but these did not see widespread use. From the 1990s, the company focused primarily on the microcontroller market.

Intel 8008 byte-oriented microprocessor

The Intel 8008 is an early byte-oriented microprocessor designed and manufactured by Intel and introduced in April 1972. It is an 8-bit CPU with an external 14-bit address bus that could address 16 KB of memory. Originally known as the 1201, the chip was commissioned by Computer Terminal Corporation (CTC) to implement an instruction set of their design for their Datapoint 2200 programmable terminal. As the chip was delayed and did not meet CTC's performance goals, the 2200 ended up using CTC's own TTL-based CPU instead. An agreement permitted Intel to market the chip to other customers after Seiko expressed an interest in using it for a calculator.

The history of computing hardware starting at 1960 is marked by the conversion from vacuum tube to solid-state devices such as the transistor and later the integrated circuit. By 1959 discrete transistors were considered sufficiently reliable and economical that they made further vacuum tube computers uncompetitive. Computer main memory slowly moved away from magnetic core memory devices to solid-state static and dynamic semiconductor memory, which greatly reduced the cost, size and power consumption of computers.

The history of computing is longer than the history of computing hardware and modern computing technology and includes the history of methods intended for pen and paper or for chalk and slate, with or without the aid of tables.

In computer architecture, 4-bit integers, memory addresses, or other data units are those that are 4 bits wide. Also, 4-bit CPU and ALU architectures are those that are based on registers, address buses, or data buses of that size. A group of four bits is also called a nibble and has 24 = 16 possible values.

Depletion-load NMOS logic form of nMOS logic family

In integrated circuits, depletion-load NMOS is a form of digital logic family that uses only a single power supply voltage, unlike earlier nMOS logic families that needed more than one different power supply voltage. Although manufacturing these integrated circuits required additional processing steps, improved switching speed and the elimination of the extra power supply made this logic family the preferred choice for many microprocessors and other logic elements.

Electronics industry global industry

The electronics industry, especially meaning consumer electronics, emerged in the 20th century and has now become a global industry worth billions of dollars. Contemporary society uses all manner of electronic devices built in automated or semi-automated factories operated by the industry. Products are assembled from integrated circuits, principally by photolithography of printed circuit boards.

The history of general-purpose CPUs is a continuation of the earlier history of computing hardware.

Stanley Mazor is an American microelectronics engineer who was born on 22 October 1941 in Chicago, Illinois. He is one of the co-inventors of the world's first microprocessor, the Intel 4004, together with Ted Hoff, Masatoshi Shima, and Federico Faggin.

The 6 µm process is the level of semiconductor process technology that was reached around 1974, by leading semiconductor companies such as Toshiba and Intel.

This is the history of science and technology in Japan.