Intel 4004

Intel 4004

Overview
The Intel 4004 was a 4-bit
4-bit
The Intel 4004, the world's first commercially available single-chip microprocessor, was a 4-bit CPU. The F-14 Tomcat's Central Air Data Computer was created a year before the 4004, but its existence was classified by the United States Navy until 1997...

 central processing unit
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...

 (CPU) released by Intel Corporation in 1971. It was the first complete CPU on one chip, and also the first commercially available microprocessor. Such a feat of integration was made possible by the use of then new silicon gate technology allowing a higher number of transistors and a faster speed than was possible before.

The first public mention of 4004 was an advertisement in the November 15, 1971 edition of Electronic News, though unconfirmed reports put the date of first delivery as early as March 1971.
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Encyclopedia
The Intel 4004 was a 4-bit
4-bit
The Intel 4004, the world's first commercially available single-chip microprocessor, was a 4-bit CPU. The F-14 Tomcat's Central Air Data Computer was created a year before the 4004, but its existence was classified by the United States Navy until 1997...

 central processing unit
Central processing unit
The central processing unit is the portion of a computer system that carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system. The CPU plays a role somewhat analogous to the brain in the computer. The term has been in...

 (CPU) released by Intel Corporation in 1971. It was the first complete CPU on one chip, and also the first commercially available microprocessor. Such a feat of integration was made possible by the use of then new silicon gate technology allowing a higher number of transistors and a faster speed than was possible before.

History and production


The first public mention of 4004 was an advertisement in the November 15, 1971 edition of Electronic News, though unconfirmed reports put the date of first delivery as early as March 1971. Packaged in a 16-pin ceramic dual in-line package
Dual in-line package
In microelectronics, a dual in-line package is an electronic device package with a rectangular housing and two parallel rows of electrical connecting pins. The package may be through-hole mounted to a printed circuit board or inserted in a socket.A DIP is usually referred to as a DIPn, where n is...

, the 4004 was the first commercially available computer processor designed and manufactured by chip
Integrated circuit
An integrated circuit or monolithic integrated circuit is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material...

 maker Intel, which had previously made semiconductor
Semiconductor
A semiconductor is a material with electrical conductivity due to electron flow intermediate in magnitude between that of a conductor and an insulator. This means a conductivity roughly in the range of 103 to 10−8 siemens per centimeter...

 memory chips. The chief designers of the chip were Federico Faggin
Federico Faggin
Federico Faggin , who received in 2010 the National Medal of Technology and Innovation by Barack Obama, the highest honor bestowed by the United States government on scientists, engineers, and inventors, at the White House in Washington, is an Italian-born and naturalized U.S...

 and Ted Hoff
Marcian Hoff
Marcian Edward "Ted" Hoff, Jr. , is one of the inventors of the microprocessor. Hoff joined Intel in 1967 as employee number 12, and is credited with coming up with the idea of using a "universal processor" rather than a variety of custom-designed circuits. His insight started the microprocessor...

 of Intel, and Masatoshi Shima
Masatoshi Shima
is a Japanese electronics engineer, who was one of the designers of the world's first microprocessor, the Intel 4004, along with Federico Faggin, Ted Hoff, and Stanley Mazor....

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

 (later of ZiLOG
Zilog
Zilog, Inc., previously known as ZiLOG , is a manufacturer of 8-bit and 24-bit microcontrollers, and is most famous for its Intel 8080-compatible Z80 series.-History:...

, founded by Faggin).

Faggin, the sole chip designer among the engineers on the MCS-4 project, was the only one with experience in MOS random logic and circuit design. He also had the crucial knowledge of the new silicon gate process technology with self-aligned gate
Self-aligned gate
A self-aligned gate, in electronics, is a transistor manufacturing feature whereby a highly doped gate electrode region of a MOSFET transistor is used as a mask for the doping of the source and drain around it...

s, which he had created at Fairchild
Fairchild Semiconductor
Fairchild Semiconductor International, Inc. is an American semiconductor company based in San Jose, California. Founded in 1957, it was a pioneer in transistor and integrated circuit manufacturing...

 in 1968. At Fairchild in 1968, Faggin also designed and manufactured the world's first commercial IC using SGT, the Fairchild 3708. As soon as he joined the Intel MOS Department he created a new random design methodology based on silicon gate, and contributed many technology and circuit design inventions that enabled a single chip microprocessor to become a reality for the first time. His methodology set the design style for all the early Intel microprocessors and later for the Zilog
Zilog
Zilog, Inc., previously known as ZiLOG , is a manufacturer of 8-bit and 24-bit microcontrollers, and is most famous for its Intel 8080-compatible Z80 series.-History:...

’s Z80
Zilog Z80
The Zilog Z80 is an 8-bit microprocessor designed by Zilog and sold from July 1976 onwards. It was widely used both in desktop and embedded computer designs as well as for military purposes...

. He also led the MCS-4 project and was responsible for its successful outcome (1970–1971). Ted Hoff, head of the Application Research Department, contributed only the architectural proposal for Busicom working with Stanley Mazor
Stanley Mazor
Stanley Mazor is an American engineer who was born on 22 October 1941 in Chicago, Illinois. He was one of the designers of the world's first microprocessor, the Intel 4004, together with Ted Hoff, Masatoshi Shima, and Federico Faggin.-Early years:...

 in 1969, then he moved on to other projects. When asked where he got the ideas for the architecture of the first microprocessor, Hoff related that Plessey
Plessey
The Plessey Company plc was a British-based international electronics, defence and telecommunications company. It originated in 1917, growing and diversifying into electronics. It expanded after the second world war by acquisition of companies and formed overseas companies...

, "a British tractor company," had donated a minicomputer to Stanford, and he had "played with it some" while he was there. Shima designed the Busicom calculator firmware and assisted Faggin during the first six months of the implementation. The manager of Intel's MOS Design Department was Leslie L. Vadász
Leslie L. Vadász
Leslie L. Vadász is a Hungarian-American engineer and manager, one of the founding members of Intel Corporation. He holds a bachelor's degree in electrical engineering from McGill University and completed AMP studies at Harvard University .He moved to the United States in 1961, first working for...

. At the time of the MCS-4 development, Vadasz's attention was completely focused on the mainstream business of semiconductor memories and he left the leadership and the management of the MCS-4 project to Faggin.

The Japanese company Busicom had designed their own special purpose LSI chipset for use in their Busicom 141-PF
Busicom
Busicom was a Japanese company that owned the rights to the first microprocessor, the Intel 4004, which they created in partnership with Intel in 1970....

 calculator
Calculator
An electronic calculator is a small, portable, usually inexpensive electronic device used to perform the basic operations of arithmetic. Modern calculators are more portable than most computers, though most PDAs are comparable in size to handheld calculators.The first solid-state electronic...

 with integrated printer and commissioned Intel to develop it for production. However, Intel determined it was too complex and would use non-standard packaging and so it was proposed that a new design produced with standard 16-pin DIP
Dual in-line package
In microelectronics, a dual in-line package is an electronic device package with a rectangular housing and two parallel rows of electrical connecting pins. The package may be through-hole mounted to a printed circuit board or inserted in a socket.A DIP is usually referred to as a DIPn, where n is...

 packaging and reduced instruction set be developed. This resulted in the 4004, which was part of a family of chips, including ROM
Read-only memory
Read-only memory is a class of storage medium used in computers and other electronic devices. Data stored in ROM cannot be modified, or can be modified only slowly or with difficulty, so it is mainly used to distribute firmware .In its strictest sense, ROM refers only...

, DRAM
Dynamic random access memory
Dynamic random-access memory is a type of random-access memory that stores each bit of data in a separate capacitor within an integrated circuit. The capacitor can be either charged or discharged; these two states are taken to represent the two values of a bit, conventionally called 0 and 1...

 and serial to parallel shift register chips. The 4004 was built of approximately 2,300 transistors and was followed the next year by the first ever 8-bit
8-bit
The first widely adopted 8-bit microprocessor was the Intel 8080, being used in many hobbyist computers of the late 1970s and early 1980s, often running the CP/M operating system. The Zilog Z80 and the Motorola 6800 were also used in similar computers...

 microprocessor, the 3,500 transistor 8008
Intel 8008
The Intel 8008 was an early byte-oriented microprocessor designed and manufactured by Intel and introduced in April 1972. It was an 8-bit CPU with an external 14-bit address bus that could address 16KB of memory...

 (and the 4040
Intel 4040
The Intel 4040 microprocessor was the successor to the Intel 4004. It was introduced in 1974. The 4040 employed a 10 μm silicon gate enhancement load PMOS technology, was made up of 3,000 transistors and could execute approximately 60,000 instructions per second.- Extensions :*Instruction Set...

, a revised 4004). It was not until the development of the 40-pin 8080
Intel 8080
The Intel 8080 was the second 8-bit microprocessor designed and manufactured by Intel and was released in April 1974. It was an extended and enhanced variant of the earlier 8008 design, although without binary compatibility...

 in 1974 that the address and data buses would be separated, giving faster and simpler access to memory.

The 4004 employed a 10-μm
Micrometre
A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...

 silicon-gate enhancement load pMOS
PMOS logic
P-type metal-oxide-semiconductor logic uses p-type metal-oxide-semiconductor field effect transistors to implement logic gates and other digital circuits...

 technology and could execute approximately 92,000 instructions per second
Instructions per second
Instructions per second is a measure of a computer's processor speed. Many reported IPS values have represented "peak" execution rates on artificial instruction sequences with few branches, whereas realistic workloads typically lead to significantly lower IPS values...

 (that is, a single instruction cycle was 10.8 microsecond
Microsecond
A microsecond is an SI unit of time equal to one millionth of a second. Its symbol is µs.A microsecond is equal to 1000 nanoseconds or 1/1000 millisecond...

s). The original clock speed design goal was 1MHz, the same as the IBM 1620 Model I
IBM 1620 Model I
The IBM 1620 Model I was the original implementation of the IBM 1620 scientific computer, introduced in 1959.This unit was produced as inexpensively as IBM could make it, in order to keep the price low...

.

The Intel 4004 was designed by physically cutting sheets of Rubylith
Rubylith
Rubylith is a brand of masking film, invented and trademarked by the Ulano Corporation. Today the brand has become genericized to the point that it has become synonymous with all coloured masking films....

 into thin strips to lay out the circuits to be printed, a process made virtually obsolete by current computer graphic design capabilities.

Name and variants


When Federico Faggin designed the MCS-4 family he also christened the chips with distinct names: 4001, 4002, 4003, and 4004, breaking away from the numbering scheme used by Intel at that time which would have required the names 1302, 1105, 1507, and 1202 respectively. Had he followed Intel's number sequence, the idea that the chips were part of a family of components intended to work seamlessly together would have been lost.

Intel's early numbering scheme for integrated circuits used a four-digit number for each component. The most significant digit position indicated the process technology used, as follows: The number "1" meant P-channel MOS, "2" indicated N-channel MOS, "3" was reserved for bipolar technology, and "5" was used for CMOS technology. No other numbers were used.

The next most significant digit was used to indicate the generic function performed by the component, as follows: "1" was used for RAM, "2" indicated random logic, "3" indicated ROM, "5" meant shift register, "6" and "7" were used for one-time programmable ROM and EPROM
EPROM
An EPROM , or erasable programmable read only memory, is a type of memory chip that retains its data when its power supply is switched off. In other words, it is non-volatile. It is an array of floating-gate transistors individually programmed by an electronic device that supplies higher voltages...

 respectively. The last two digits of the number were used to indicate the sequential number in the development of the component.

The 8008 microprocessor was originally called 1201, according to Intel’s naming conventions. Before its market introduction, the 1201 was renamed 8008, following the new naming convention started by Faggin with the 4001/2/3/4.

The 4004 was part of the MCS-4 family of LSI chips that could be used to build digital computers with varying amounts of memory. The other members of the MCS-4 family were memories and input/output circuits, which while not part of a CPU are necessary to implement a complete computer. Specifically:
  • the 4001 was a ROM (read-only memory) with four lines of output
  • the 4002 was a RAM (random access memory) with four lines of input/output
  • the 4003 was a static shift register to be used for expanding the I/O lines, for example, for keyboard scanning or for controlling a printer.


The 4004 included control functions for memory and I/O, which are not normally handled by the microprocessor.

Technical specifications


  • Maximum clock speed was 740 kHz
  • Instruction cycle time: 10.8 µs (8 clock cycles / instruction cycle)
  • Instruction execution time 1 or 2 instruction cycles (10.8 or 21.6 µs), 46300 to 92600 instructions per second
  • Separate program and data storage. Contrary to Harvard architecture
    Harvard architecture
    The Harvard architecture is a computer architecture with physically separate storage and signal pathways for instructions and data. The term originated from the Harvard Mark I relay-based computer, which stored instructions on punched tape and data in electro-mechanical counters...

     designs, however, which use separate bus
    Computer bus
    In computer architecture, a bus is a subsystem that transfers data between components inside a computer, or between computers.Early computer buses were literally parallel electrical wires with multiple connections, but the term is now used for any physical arrangement that provides the same...

    es, the 4004, with its need to keep pin count down, used a single multiplexed
    Multiplexer
    In electronics, a multiplexer is a device that selects one of several analog or digital input signals and forwards the selected input into a single line. A multiplexer of 2n inputs has n select lines, which are used to select which input line to send to the output...

     4-bit bus for transferring:
    • 12-bit addresses
    • 8-bit instructions
    • 4-bit data words
  • Instruction set
    Instruction set
    An instruction set, or instruction set architecture , is the part of the computer architecture related to programming, including the native data types, instructions, registers, addressing modes, memory architecture, interrupt and exception handling, and external I/O...

     contained 46 instructions (of which 41 were 8 bits wide and 5 were 16 bits wide)
  • Register set contained 16 registers of 4 bits each
  • Internal subroutine
    Subroutine
    In computer science, a subroutine is a portion of code within a larger program that performs a specific task and is relatively independent of the remaining code....

     stack
    Stack-based memory allocation
    Stacks in computing architectures are regions of memory where data is added or removed in a last-in-first-out manner.In most modern computer systems, each thread has a reserved region of memory referred to as its stack. When a function executes, it may add some of its state data to the top of the...

     3 levels deep.

Support chips

  • 4001: 256-byte
    Byte
    The byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits. Historically, a byte was the number of bits used to encode a single character of text in a computer and for this reason it is the basic addressable element in many computer...

     ROM (256 8-bit program instructions), and one built-in 4-bit I/O
    Input/output
    In computing, input/output, or I/O, refers to the communication between an information processing system , and the outside world, possibly a human, or another information processing system. Inputs are the signals or data received by the system, and outputs are the signals or data sent from it...

     port. A 4001 ROM+I/O chip cannot be used in a system along with a 4008/4009 pair.
  • 4002: 40-byte RAM
    Random-access memory
    Random access memory is a form of computer data storage. Today, it takes the form of integrated circuits that allow stored data to be accessed in any order with a worst case performance of constant time. Strictly speaking, modern types of DRAM are therefore not random access, as data is read in...

     (80 4-bit data words), and one built-in 4-bit output port; the RAM portion of the chip is organized into four "registers" of 20 4-bit words:
    • 16 data words (used for mantissa
      Significand
      The significand is part of a floating-point number, consisting of its significant digits. Depending on the interpretation of the exponent, the significand may represent an integer or a fraction.-Examples:...

       digits in the original calculator design)
    • 4 status words (used for exponent digits and signs in the original calculator design)
  • 4003: 10-bit parallel output shift register
    Shift register
    In digital circuits, a shift register is a cascade of flip flops, sharing the same clock, which has the output of any one but the last flip-flop connected to the "data" input of the next one in the chain, resulting in a circuit that shifts by one position the one-dimensional "bit array" stored in...

     for scanning keyboards, displays, printers, etc.
  • 4008: 8-bit address latch for access to standard memory chips, and one built-in 4-bit chip select and I/O port
  • 4009: program and I/O access converter to standard memory and I/O chips
  • 4269: keyboard/display interface
  • 4289: memory interface (combined functions of 4008 and 4009)

Use


The first commercial product to use a microprocessor was the Busicom
Busicom
Busicom was a Japanese company that owned the rights to the first microprocessor, the Intel 4004, which they created in partnership with Intel in 1970....

 calculator 141-PF.

According to Nick Tredennick
Nick Tredennick
Harry L. Tredennick is an American manager, inventor, VLSI design engineer and author who was involved in the development for Motorola's MC68000 and for IBM's Micro/370 microprocessors. Tredennick was named a Fellow of the IEEE for contributions to microprocessor design.-Education:Tredennick...

, a microprocessor designer and expert witness to the Boone/Hyatt patent case:
A popular myth has it that Pioneer 10
Pioneer 10
Pioneer 10 is a 258-kilogram robotic space probe that completed the first interplanetary mission to Jupiter, and became the first spacecraft to achieve escape velocity from the Solar System. The project was managed by the NASA Ames Research Center and the contract for the construction of the...

, the first spacecraft to leave the solar system, used an Intel 4004 microprocessor. According to Dr. Larry Lasher of Ames Research Center, the Pioneer team did evaluate the 4004, but decided it was too new at the time to include in any of the Pioneer projects. The myth was repeated by Federico Faggin himself in a lecture for the Computer History Museum
Computer History Museum
The Computer History Museum is a museum established in 1996 in Mountain View, California, USA. The Museum is dedicated to preserving and presenting the stories and artifacts of the information age, and exploring the computing revolution and its impact on our lives.-History:The museum's origins...

 in 2006.

Legacy and value


On November 15, 2006, the 35th anniversary of the 4004, Intel celebrated by releasing the chip's schematic
Schematic
A schematic diagram represents the elements of a system using abstract, graphic symbols rather than realistic pictures. A schematic usually omits all details that are not relevant to the information the schematic is intended to convey, and may add unrealistic elements that aid comprehension...

s, mask works, and user manual.

On October 15, 2010, Faggin, Hoff, and Mazor were awarded the National Medal of Technology and Innovation by President Barack Obama
Barack Obama
Barack Hussein Obama II is the 44th and current President of the United States. He is the first African American to hold the office. Obama previously served as a United States Senator from Illinois, from January 2005 until he resigned following his victory in the 2008 presidential election.Born in...

 for their pioneering work on the 4004.

Patents


August 14, 1973. Faggin, Federico: Power supply settable bi-stable circuit. June 28, 1974. Hoff, Marcian; Mazor, Stanley; Faggin, Federico: Memory system for multi-chip digital computer.

Historical documents

  • Faggin F., Capocaccia F. "A New Integrated MOS Shift Register”, Proceedings XV International Electronics Scientific Congress, Rome, April 1968, pp. 143–152. This paper describes a novel static MOS shift register, developed at SGS-Fairchild (now ST Micro) at the end of 1967, before Federico Faggin joined Fairchild's R&D in Palo Alto (Ca) in February 1968. Faggin later used this new shift register in the MCS-4 chips, including the 4004.
  • Cover and abstract of the IEDM (International Electron Devices Meeting) Program (October 1968). The Silicon Gate Technology (SGT) was first presented by its developer, Federico Faggin, at the IEDM on October 23, 1968 in Washington, D.C. It was the only commercial process technology for the fabrication of MOS integrated circuits with self-aligned gate that was later universally adopted by the semiconductor industry. The SGT was the first technology to produce commercial dynamic RAMs, CCD image sensors, non volatile memories and the microprocessor, providing for the first time all the fundamental elements of a general purpose computer with LSI integrated circuits.
  • Cover of Electronics Magazine (September 29, 1969). The Electronics article introduces the Fairchild 3708, designed by Federico Faggin in 1968. It was the world's first commercial integrated circuit using the Silicon Gate Technology, proving its viability.
  • Initials F.F. (Federico Faggin) on the 4004 design (1971). The 4004 bears the initials F.F. of its designer, Federico Faggin, etched on one corner of the chip. Signing the chip was a spontaneous gesture of proud authorship and was also an original idea imitated after him by many Intel designers.
  • Busicom Calculator Engineering Prototype (1971). (Gift of Federico Faggin to the Computer History Museum, Mountain View, CA). The CHM collection catalog shows pictures of the engineering prototype of the Busicom 141-PF desktop calculator. The engineering prototype used the world’s first microprocessor to have ever been produced. This one-of-a-kind prototype was a personal present by Busicom’s president Mr. Yoshio Kojima to Federico Faggin for his successful leadership of the design and development of the 4004 and three other memory and I/O chips (the MCS-4 chipset). After keeping it in his home for 25 years, Faggin donated it to the CHM in 1996.
  • F. Faggin and M.E. Hoff: "Standard parts and custom design merge in four-chip processor kit". Electronics/April 24, 1972, pp. 112–116
  • F. Faggin, M.Shima, M.E. Hoff, Jr., H. Feeney, S. Mazor: "The MCS-4 An LSI micro computer system". IEEE '72 Region Six Conference

Further reading

  • Federico Faggin, Marcian E. Hoff Jr., Stanley Mazor and Masatoshi Shima. The history of the 4004. IEEE Micro, 16(6):10-20, December 1996. "The 4004 design team tells its story."
  • Intel 4004 Microprocessor 35th Anniversary - Live recording of presentations by Ted Hoff and Federico Faggin at the Computer History Museum for the 35th anniversary of the first microprocessor. (youtube.com
    YouTube
    YouTube is a video-sharing website, created by three former PayPal employees in February 2005, on which users can upload, view and share videos....

    )
  • IEEE Solid State Circuits Magazine, Winter 2009 Vol.1 No.1. "The 4004 microprocessor of Faggin, Hoff, Mazor, and Shima".

External links