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Integrated circuit

An integrated circuit (IC), also known as a microchip, computer chip, or simply chip, is a small electronic device made up of multiple interconnected electronic components such as transistors, resistors, and capacitors. These components are etched onto a small piece of semiconductor material, usually silicon. Integrated circuits are used in a wide range of electronic devices, including computers, smartphones, and televisions, to perform various functions such as processing and storing information. They have greatly impacted the field of electronics by enabling device miniaturization and enhanced functionality.

Integrated circuits are orders of magnitude smaller, faster, and less expensive than those constructed of discrete components, allowing a large transistor count.

The IC's mass production capability, reliability, and building-block approach to integrated circuit design have ensured the rapid adoption of standardized ICs in place of designs using discrete transistors. ICs are now used in virtually all electronic equipment and have revolutionized the world of electronics. Computers, mobile phones, and other home appliances are now essential parts of the structure of modern societies, made possible by the small size and low cost of ICs such as modern computer processors and microcontrollers.

Very-large-scale integration was made practical by technological advancements in semiconductor device fabrication. Since their origins in the 1960s, the size, speed, and capacity of chips have progressed enormously, driven by technical advances that fit more and more transistors on chips of the same size – a modern chip may have many billions of transistors in an area the size of a human fingernail. These advances, roughly following Moore's law, make the computer chips of today possess millions of times the capacity and thousands of times the speed of the computer chips of the early 1970s.

ICs have three main advantages over circuits constructed out of discrete components: size, cost and performance. The size and cost is low because the chips, with all their components, are printed as a unit by photolithography rather than being constructed one transistor at a time. Furthermore, packaged ICs use much less material than discrete circuits. Performance is high because the IC's components switch quickly and consume comparatively little power because of their small size and proximity. The main disadvantage of ICs is the high initial cost of designing them and the enormous capital cost of factory construction. This high initial cost means ICs are only commercially viable when high production volumes are anticipated.

Terminology
An integrated circuit is defined as: "A circuit in which all or some of the circuit elements are inseparably associated and electrically interconnected so that it is considered to be indivisible for the purposes of construction and commerce." In strict usage, integrated circuit refers to the single-piece circuit construction originally known as a monolithic integrated circuit, built on a single piece of silicon. In general usage, circuits not meeting this strict definition are sometimes referred to as ICs, which are constructed using many different technologies, e.g. 3D IC, 2.5D IC, MCM, thin-film transistors, thick-film technologies, or hybrid integrated circuits. The choice of terminology frequently appears in discussions related to whether Moore's Law is obsolete.

History
An early attempt at combining several components in one device (like modern ICs) was the Loewe 3NF vacuum tube first made in 1926. Unlike ICs, it was designed with the purpose of tax avoidance, as in Germany, radio receivers had a tax that was levied depending on how many tube holders a radio receiver had. It allowed radio receivers to have a single tube holder. One million were manufactured, and were "a first step in integration of radioelectronic devices". The device contained an amplifier, composed of three triodes, two capacitors and four resistors in a six-pin device.

Early concepts of an integrated circuit go back to 1949, when German engineer Werner Jacobi (Siemens AG) filed a patent for an integrated-circuit-like semiconductor amplifying device showing five transistors on a common substrate in a three-stage amplifier arrangement. Jacobi disclosed small and cheap hearing aids as typical industrial applications of his patent. An immediate commercial use of his patent has not been reported.

Another early proponent of the concept was Geoffrey Dummer (1909–2002), a radar scientist working for the Royal Radar Establishment of the British Ministry of Defence. Dummer presented the idea to the public at the Symposium on Progress in Quality Electronic Components in Washington, D.C., on 7 May 1952. He gave many symposia publicly to propagate his ideas and unsuccessfully attempted to build such a circuit in 1956. Between 1953 and 1957, Sidney Darlington and Yasuo Tarui (Electrotechnical Laboratory) proposed similar chip designs where several transistors could share a common active area, but there was no electrical isolation to separate them from each other.

The monolithic integrated circuit chip was enabled by the inventions of the planar process by Jean Hoerni and p–n junction isolation by Kurt Lehovec. Hoerni's invention was built on Mohamed M. Atalla's work on surface passivation, as well as Fuller and Ditzenberger's work on the diffusion of boron and phosphorus impurities into silicon, Carl Frosch and Lincoln Derick's work on surface protection, and Chih-Tang Sah's work on diffusion masking by the oxide.

The first integrated circuits

A precursor idea to the IC was to create small ceramic substrates (so-called micromodules), each containing a single miniaturized component. Components could then be integrated and wired into a bidimensional or tridimensional compact grid. This idea, which seemed very promising in 1957, was proposed to the US Army by Jack Kilby and led to the short-lived Micromodule Program (similar to 1951's Project Tinkertoy). However, as the project was gaining momentum, Kilby came up with a new, revolutionary design: the IC.

Newly employed by Texas Instruments, Kilby recorded his initial ideas concerning the integrated circuit in July 1958, successfully demonstrating the first working example of an integrated circuit on 12 September 1958. In his patent application of 6 February 1959, Kilby described his new device as "a body of semiconductor material … wherein all the components of the electronic circuit are completely integrated". The first customer for the new invention was the US Air Force. Kilby won the 2000 Nobel Prize in physics for his part in the invention of the integrated circuit.

However, Kilby's invention was not a true monolithic integrated circuit chip since it had external gold-wire connections, which would have made it difficult to mass-produce. Half a year after Kilby, Robert Noyce at Fairchild Semiconductor invented the first true monolithic IC chip. More practical than Kilby's implementation, Noyce's chip was made of silicon, whereas Kilby's was made of germanium, and Noyce's was fabricated using the planar process, developed in early 1959 by his colleague Jean Hoerni and included the critical on-chip aluminum interconnecting lines. Modern IC chips are based on Noyce's monolithic IC, rather than Kilby's.

NASA's Apollo Program was the largest single consumer of integrated circuits between 1961 and 1965.

TTL integrated circuits
Transistor–transistor logic (TTL) was developed by James L. Buie in the early 1960s at TRW Inc. TTL became the dominant integrated circuit technology during the 1970s to early 1980s.

Dozens of TTL integrated circuits were a standard method of construction for the processors of minicomputers and mainframe computers. Computers such as IBM 360 mainframes, PDP-11 minicomputers and the desktop Datapoint 2200 were built from bipolar integrated circuits, either TTL or the even faster emitter-coupled logic (ECL).

EPROM
An EPROM is a type of chip whose concept was developed by Israeli electrical engineer, Dov Frohman in 1969 and developed in practice in 1971 while Frohman worked for Intel.

MOS integrated circuits
Nearly all modern IC chips are metal–oxide–semiconductor (MOS) integrated circuits, built from MOSFETs (metal–oxide–silicon field-effect transistors). The MOSFET (also known as the MOS transistor), which was invented by Mohamed M. Atalla and Dawon Kahng at Bell Labs in 1959, made it possible to build high-density integrated circuits. In contrast to bipolar transistors which required a number of steps for the p–n junction isolation of transistors on a chip, MOSFETs required no such steps but could be easily isolated from each other. Its advantage for integrated circuits was pointed out by Dawon Kahng in 1961. The list of IEEE milestones includes the first integrated circuit by Kilby in 1958, Hoerni's planar process and Noyce's planar IC in 1959, and the MOSFET by Atalla and Kahng in 1959.

The earliest experimental MOS IC to be fabricated was a 16-transistor chip built by Fred Heiman and Steven Hofstein at RCA in 1962. General Microelectronics later introduced the first commercial MOS integrated circuit in 1964, a 120-transistor shift register developed by Robert Norman. By 1964, MOS chips had reached higher transistor density and lower manufacturing costs than bipolar chips. MOS chips further increased in complexity at a rate predicted by Moore's law, leading to large-scale integration (LSI) with hundreds of transistors on a single MOS chip by the late 1960s.

Following the development of the self-aligned gate (silicon-gate) MOSFET by Robert Kerwin, Donald Klein and John Sarace at Bell Labs in 1967, the first silicon-gate MOS IC technology with self-aligned gates, the basis of all modern CMOS integrated circuits, was developed at Fairchild Semiconductor by Federico Faggin in 1968. The application of MOS LSI chips to computing was the basis for the first microprocessors, as engineers began recognizing that a complete computer processor could be contained on a single MOS LSI chip. This led to the inventions of the microprocessor and the microcontroller by the early 1970s. During the early 1970s, MOS integrated circuit technology enabled the very large-scale integration (VLSI) of more than 10,000 transistors on a single chip.

At first, MOS-based computers only made sense when high density was required, such as aerospace and pocket calculators. Computers built entirely from TTL, such as the 1970 Datapoint 2200, were much faster and more powerful than single-chip MOS microprocessors such as the 1972 Intel 8008 until the early 1980s.

Advances in IC technology, primarily smaller features and larger chips, have allowed the number of MOS transistors in an integrated circuit to double every two years, a trend known as Moore's law. Moore originally stated it would double every year, but he went on to change the claim to every two years in 1975. This increased capacity has been used to decrease cost and increase functionality. In general, as the feature size shrinks, almost every aspect of an IC's operation improves. The cost per transistor and the switching power consumption per transistor goes down, while the memory capacity and speed go up, through the relationships defined by Dennard scaling (MOSFET scaling). Because speed, capacity, and power consumption gains are apparent to the end user, there is fierce competition among the manufacturers to use finer geometries. Over the years, transistor sizes have decreased from tens of microns in the early 1970s to 10 nanometers in 2017 with a corresponding million-fold increase in transistors per unit area. As of 2016, typical chip areas range from a few square millimeters to around 600 mm2, with up to 25 million transistors per mm2.

The expected shrinking of feature sizes and the needed progress in related areas was forecast for many years by the International Technology Roadmap for Semiconductors (ITRS). The final ITRS was issued in 2016, and it is being replaced by the International Roadmap for Devices and Systems.

Initially, ICs were strictly electronic devices. The success of ICs has led to the integration of other technologies, in an attempt to obtain the same advantages of small size and low cost. These technologies include mechanical devices, optics, and sensors. , the vast majority of all transistors are MOSFETs fabricated in a single layer on one side of a chip of silicon in a flat two-dimensional planar process. Researchers have produced prototypes of several promising alternatives, such as:
 * Charge-coupled devices, and the closely related active-pixel sensors, are chips that are sensitive to light. They have largely replaced photographic film in scientific, medical, and consumer applications. Billions of these devices are now produced each year for applications such as cellphones, tablets, and digital cameras. This sub-field of ICs won the Nobel Prize in 2009.
 * Very small mechanical devices driven by electricity can be integrated onto chips, a technology known as microelectromechanical systems (MEMS). These devices were developed in the late 1980s and are used in a variety of commercial and military applications. Examples include DLP projectors, inkjet printers, and accelerometers and MEMS gyroscopes used to deploy automobile airbags.
 * Since the early 2000s, the integration of optical functionality (optical computing) into silicon chips has been actively pursued in both academic research and in industry resulting in the successful commercialization of silicon based integrated optical transceivers combining optical devices (modulators, detectors, routing) with CMOS based electronics. Photonic integrated circuits that use light such as Lightelligence's PACE (Photonic Arithmetic Computing Engine) also being developed, using the emerging field of physics known as photonics.
 * Integrated circuits are also being developed for sensor applications in medical implants or other bioelectronic devices. Special sealing techniques have to be applied in such biogenic environments to avoid corrosion or biodegradation of the exposed semiconductor materials.
 * various approaches to stacking several layers of transistors to make a three-dimensional integrated circuit (3DIC), such as through-silicon via, "monolithic 3D", stacked wire bonding, and other methodologies.
 * transistors built from other materials: graphene transistors, molybdenite transistors, carbon nanotube field-effect transistor, gallium nitride transistor, transistor-like nanowire electronic devices, organic field-effect transistor, etc.
 * fabricating transistors over the entire surface of a small sphere of silicon.
 * modifications to the substrate, typically to make "flexible transistors" for a flexible display or other flexible electronics, possibly leading to a roll-away computer.

As it becomes more difficult to manufacture ever smaller transistors, companies are using multi-chip modules, three-dimensional integrated circuits, package on package, High Bandwidth Memory and through-silicon vias with die stacking to increase performance and reduce size, without having to reduce the size of the transistors. Such techniques are collectively known as advanced packaging. Advanced packaging is mainly divided into 2.5D and 3D packaging. 2.5D describes approaches such as multi-chip modules while 3D describes approaches where dies are stacked in one way or another, such as package on package and high bandwidth memory. All approaches involve 2 or more dies in a single package. Alternatively, approaches such as 3D NAND stack multiple layers on a single die. A technique has been demonstrated to include microfluidic cooling on integrated circuits, to improve cooling performance as well as peltier thermoelectric coolers on solder bumps, or thermal solder bumps used exclusively for heat dissipation, used in flip-chip.

Design
The cost of designing and developing a complex integrated circuit is quite high, normally in the multiple tens of millions of dollars. Therefore, it only makes economic sense to produce integrated circuit products with high production volume, so the non-recurring engineering (NRE) costs are spread across typically millions of production units.

Modern semiconductor chips have billions of components, and are far too complex to be designed by hand. Software tools to help the designer are essential. Electronic design automation (EDA), also referred to as electronic computer-aided design (ECAD), is a category of software tools for designing electronic systems, including integrated circuits. The tools work together in a design flow that engineers use to design, verify, and analyze entire semiconductor chips. Some of the latest EDA tools use artificial intelligence (AI) to help engineers save time and improve chip performance.

Types
Integrated circuits can be broadly classified into analog, digital and mixed signal, consisting of analog and digital signaling on the same IC.

Digital integrated circuits can contain billions of logic gates, flip-flops, multiplexers, and other circuits in a few square millimeters. The small size of these circuits allows high speed, low power dissipation, and reduced manufacturing cost compared with board-level integration. These digital ICs, typically microprocessors, DSPs, and microcontrollers, use boolean algebra to process "one" and "zero" signals.

Among the most advanced integrated circuits are the microprocessors or "cores", used in personal computers, cell-phones, microwave ovens, etc. Several cores may be integrated together in a single IC or chip. Digital memory chips and application-specific integrated circuits (ASICs) are examples of other families of integrated circuits.

In the 1980s, programmable logic devices were developed. These devices contain circuits whose logical function and connectivity can be programmed by the user, rather than being fixed by the integrated circuit manufacturer. This allows a chip to be programmed to do various LSI-type functions such as logic gates, adders and registers. Programmability comes in various forms – devices that can be programmed only once, devices that can be erased and then re-programmed using UV light, devices that can be (re)programmed using flash memory, and field-programmable gate arrays (FPGAs) which can be programmed at any time, including during operation. Current FPGAs can (as of 2016) implement the equivalent of millions of gates and operate at frequencies up to 1 GHz.

Analog ICs, such as sensors, power management circuits, and operational amplifiers (op-amps), process continuous signals, and perform analog functions such as amplification, active filtering, demodulation, and mixing.

ICs can combine analog and digital circuits on a chip to create functions such as analog-to-digital converters and digital-to-analog converters. Such mixed-signal circuits offer smaller size and lower cost, but must account for signal interference. Prior to the late 1990s, radios could not be fabricated in the same low-cost CMOS processes as microprocessors. But since 1998, radio chips have been developed using RF CMOS processes. Examples include Intel's DECT cordless phone, or 802.11 (Wi-Fi) chips created by Atheros and other companies.

Modern electronic component distributors often further sub-categorize integrated circuits:
 * Digital ICs are categorized as logic ICs (such as microprocessors and microcontrollers), memory chips (such as MOS memory and floating-gate memory), interface ICs (level shifters, serializer/deserializer, etc.), power management ICs, and programmable devices.
 * Analog ICs are categorized as linear integrated circuits and RF circuits (radio frequency circuits).
 * Mixed-signal integrated circuits are categorized as data acquisition ICs (including A/D converters, D/A converters, digital potentiometers), clock/timing ICs, switched capacitor (SC) circuits, and RF CMOS circuits.
 * Three-dimensional integrated circuits (3D ICs) are categorized into through-silicon via (TSV) ICs and Cu-Cu connection ICs.

Fabrication

The semiconductors of the periodic table of the chemical elements were identified as the most likely materials for a solid-state vacuum tube. Starting with copper oxide, proceeding to germanium, then silicon, the materials were systematically studied in the 1940s and 1950s. Today, monocrystalline silicon is the main substrate used for ICs although some III-V compounds of the periodic table such as gallium arsenide are used for specialized applications like LEDs, lasers, solar cells and the highest-speed integrated circuits. It took decades to perfect methods of creating crystals with minimal defects in semiconducting materials' crystal structure.

Semiconductor ICs are fabricated in a planar process which includes three key process steps – photolithography, deposition (such as chemical vapor deposition), and etching. The main process steps are supplemented by doping and cleaning. More recent or high-performance ICs may instead use multi-gate FinFET or GAAFET transistors instead of planar ones, starting at the 22 nm node (Intel) or 16/14 nm nodes.

Mono-crystal silicon wafers are used in most applications (or for special applications, other semiconductors such as gallium arsenide are used). The wafer need not be entirely silicon. Photolithography is used to mark different areas of the substrate to be doped or to have polysilicon, insulators or metal (typically aluminium or copper) tracks deposited on them. Dopants are impurities intentionally introduced to a semiconductor to modulate its electronic properties. Doping is the process of adding dopants to a semiconductor material.
 * Integrated circuits are composed of many overlapping layers, each defined by photolithography, and normally shown in different colors. Some layers mark where various dopants are diffused into the substrate (called diffusion layers), some define where additional ions are implanted (implant layers), some define the conductors (doped polysilicon or metal layers), and some define the connections between the conducting layers (via or contact layers). All components are constructed from a specific combination of these layers.
 * In a self-aligned CMOS process, a transistor is formed wherever the gate layer (polysilicon or metal) crosses a diffusion layer (this is called "the self-aligned gate").
 * Capacitive structures, in form very much like the parallel conducting plates of a traditional electrical capacitor, are formed according to the area of the "plates", with insulating material between the plates. Capacitors of a wide range of sizes are common on ICs.
 * Meandering stripes of varying lengths are sometimes used to form on-chip resistors, though most logic circuits do not need any resistors. The ratio of the length of the resistive structure to its width, combined with its sheet resistivity, determines the resistance.
 * More rarely, inductive structures can be built as tiny on-chip coils, or simulated by gyrators.

Since a CMOS device only draws current on the transition between logic states, CMOS devices consume much less current than bipolar junction transistor devices.

A random-access memory is the most regular type of integrated circuit; the highest density devices are thus memories; but even a microprocessor will have memory on the chip. (See the regular array structure at the bottom of the first image.) Although the structures are intricate – with widths which have been shrinking for decades – the layers remain much thinner than the device widths. The layers of material are fabricated much like a photographic process, although light waves in the visible spectrum cannot be used to "expose" a layer of material, as they would be too large for the features. Thus photons of higher frequencies (typically ultraviolet) are used to create the patterns for each layer. Because each feature is so small, electron microscopes are essential tools for a process engineer who might be debugging a fabrication process.

Each device is tested before packaging using automated test equipment (ATE), in a process known as wafer testing, or wafer probing. The wafer is then cut into rectangular blocks, each of which is called a die. Each good die (plural dice, dies, or die) is then connected into a package using aluminium (or gold) bond wires which are thermosonically bonded to pads, usually found around the edge of the die. Thermosonic bonding was first introduced by A. Coucoulas which provided a reliable means of forming these vital electrical connections to the outside world. After packaging, the devices go through final testing on the same or similar ATE used during wafer probing. Industrial CT scanning can also be used. Test cost can account for over 25% of the cost of fabrication on lower-cost products, but can be negligible on low-yielding, larger, or higher-cost devices.

, a fabrication facility (commonly known as a semiconductor fab) can cost over US$12 billion to construct. The cost of a fabrication facility rises over time because of increased complexity of new products; this is known as Rock's law. Such a facility features:
 * The wafers up to 300 mm in diameter (wider than a common dinner plate).
 * , 5 nm transistors.
 * Copper interconnects where copper wiring replaces aluminum for interconnects.
 * Low-κ dielectric insulators.
 * Silicon on insulator (SOI).
 * Strained silicon in a process used by IBM known as Strained silicon directly on insulator (SSDOI).
 * Multigate devices such as tri-gate transistors.

ICs can be manufactured either in-house by integrated device manufacturers (IDMs) or using the foundry model. IDMs are vertically integrated companies (like Intel and Samsung) that design, manufacture and sell their own ICs, and may offer design and/or manufacturing (foundry) services to other companies (the latter often to fabless companies). In the foundry model, fabless companies (like Nvidia) only design and sell ICs and outsource all manufacturing to pure play foundries such as TSMC. These foundries may offer IC design services.

Packaging

The earliest integrated circuits were packaged in ceramic flat packs, which continued to be used by the military for their reliability and small size for many years. Commercial circuit packaging quickly moved to the dual in-line package (DIP), first in ceramic and later in plastic, which is commonly cresol-formaldehyde-novolac. In the 1980s pin counts of VLSI circuits exceeded the practical limit for DIP packaging, leading to pin grid array (PGA) and leadless chip carrier (LCC) packages. Surface mount packaging appeared in the early 1980s and became popular in the late 1980s, using finer lead pitch with leads formed as either gull-wing or J-lead, as exemplified by the small-outline integrated circuit (SOIC) package – a carrier which occupies an area about 30–50% less than an equivalent DIP and is typically 70% thinner. This package has "gull wing" leads protruding from the two long sides and a lead spacing of 0.050 inches.

In the late 1990s, plastic quad flat pack (PQFP) and thin small-outline package (TSOP) packages became the most common for high pin count devices, though PGA packages are still used for high-end microprocessors.

Ball grid array (BGA) packages have existed since the 1970s. Flip-chip Ball Grid Array packages, which allow for a much higher pin count than other package types, were developed in the 1990s. In an FCBGA package, the die is mounted upside-down (flipped) and connects to the package balls via a package substrate that is similar to a printed-circuit board rather than by wires. FCBGA packages allow an array of input-output signals (called Area-I/O) to be distributed over the entire die rather than being confined to the die periphery. BGA devices have the advantage of not needing a dedicated socket but are much harder to replace in case of device failure.

Intel transitioned away from PGA to land grid array (LGA) and BGA beginning in 2004, with the last PGA socket released in 2014 for mobile platforms. , AMD uses PGA packages on mainstream desktop processors, BGA packages on mobile processors, and high-end desktop and server microprocessors use LGA packages.

Electrical signals leaving the die must pass through the material electrically connecting the die to the package, through the conductive traces (paths) in the package, through the leads connecting the package to the conductive traces on the printed circuit board. The materials and structures used in the path these electrical signals must travel have very different electrical properties, compared to those that travel to different parts of the same die. As a result, they require special design techniques to ensure the signals are not corrupted, and much more electric power than signals confined to the die itself.

When multiple dies are put in one package, the result is a system in package, abbreviated SiP. A multi-chip module (MCM), is created by combining multiple dies on a small substrate often made of ceramic. The distinction between a large MCM and a small printed circuit board is sometimes fuzzy.

Packaged integrated circuits are usually large enough to include identifying information. Four common sections are the manufacturer's name or logo, the part number, a part production batch number and serial number, and a four-digit date-code to identify when the chip was manufactured. Extremely small surface-mount technology parts often bear only a number used in a manufacturer's lookup table to find the integrated circuit's characteristics.

The manufacturing date is commonly represented as a two-digit year followed by a two-digit week code, such that a part bearing the code 8341 was manufactured in week 41 of 1983, or approximately in October 1983.

Intellectual property
The possibility of copying by photographing each layer of an integrated circuit and preparing photomasks for its production on the basis of the photographs obtained is a reason for the introduction of legislation for the protection of layout designs. The US Semiconductor Chip Protection Act of 1984 established intellectual property protection for photomasks used to produce integrated circuits.

A diplomatic conference held at Washington, D.C., in 1989 adopted a Treaty on Intellectual Property in Respect of Integrated Circuits, also called the Washington Treaty or IPIC Treaty. The treaty is currently not in force, but was partially integrated into the TRIPS agreement.

There are several United States patents connected to the integrated circuit, which include patents by J.S. Kilby, , and by R.F. Stewart.

National laws protecting IC layout designs have been adopted in a number of countries, including Japan, the EC, the UK, Australia, and Korea. The UK enacted the Copyright, Designs and Patents Act, 1988, c. 48, § 213, after it initially took the position that its copyright law fully protected chip topographies. See British Leyland Motor Corp. v. Armstrong Patents Co.

Criticisms of inadequacy of the UK copyright approach as perceived by the US chip industry are summarized in further chip rights developments.

Australia passed the Circuit Layouts Act of 1989 as a sui generis form of chip protection. Korea passed the Act Concerning the Layout-Design of Semiconductor Integrated Circuits in 1992.

Generations
In the early days of simple integrated circuits, the technology's large scale limited each chip to only a few transistors, and the low degree of integration meant the design process was relatively simple. Manufacturing yields were also quite low by today's standards. As metal–oxide–semiconductor (MOS) technology progressed, millions and then billions of MOS transistors could be placed on one chip, and good designs required thorough planning, giving rise to the field of electronic design automation, or EDA. Some SSI and MSI chips, like discrete transistors, are still mass-produced, both to maintain old equipment and build new devices that require only a few gates. The 7400 series of TTL chips, for example, has become a de facto standard and remains in production.

Small-scale integration (SSI)
The first integrated circuits contained only a few transistors. Early digital circuits containing tens of transistors provided a few logic gates, and early linear ICs such as the Plessey SL201 or the Philips TAA320 had as few as two transistors. The number of transistors in an integrated circuit has increased dramatically since then. The term "large scale integration" (LSI) was first used by IBM scientist Rolf Landauer when describing the theoretical concept; that term gave rise to the terms "small-scale integration" (SSI), "medium-scale integration" (MSI), "very-large-scale integration" (VLSI), and "ultra-large-scale integration" (ULSI). The early integrated circuits were SSI.

SSI circuits were crucial to early aerospace projects, and aerospace projects helped inspire development of the technology. Both the Minuteman missile and Apollo program needed lightweight digital computers for their inertial guidance systems. Although the Apollo Guidance Computer led and motivated integrated-circuit technology, it was the Minuteman missile that forced it into mass-production. The Minuteman missile program and various other United States Navy programs accounted for the total $4 million integrated circuit market in 1962, and by 1968, U.S. Government spending on space and defense still accounted for 37% of the $312 million total production.

The demand by the U.S. Government supported the nascent integrated circuit market until costs fell enough to allow IC firms to penetrate the industrial market and eventually the consumer market. The average price per integrated circuit dropped from $50.00 in 1962 to $2.33 in 1968. Integrated circuits began to appear in consumer products by the turn of the 1970s decade. A typical application was FM inter-carrier sound processing in television receivers.

The first application MOS chips were small-scale integration (SSI) chips. Following Mohamed M. Atalla's proposal of the MOS integrated circuit chip in 1960, the earliest experimental MOS chip to be fabricated was a 16-transistor chip built by Fred Heiman and Steven Hofstein at RCA in 1962. The first practical application of MOS SSI chips was for NASA satellites.

Medium-scale integration (MSI)
The next step in the development of integrated circuits introduced devices which contained hundreds of transistors on each chip, called "medium-scale integration" (MSI).

MOSFET scaling technology made it possible to build high-density chips. By 1964, MOS chips had reached higher transistor density and lower manufacturing costs than bipolar chips.

In 1964, Frank Wanlass demonstrated a single-chip 16-bit shift register he designed, with a then-incredible 120 MOS transistors on a single chip. The same year, General Microelectronics introduced the first commercial MOS integrated circuit chip, consisting of 120 p-channel MOS transistors. It was a 20-bit shift register, developed by Robert Norman and Frank Wanlass. MOS chips further increased in complexity at a rate predicted by Moore's law, leading to chips with hundreds of MOSFETs on a chip by the late 1960s.

Large-scale integration (LSI)
Further development, driven by the same MOSFET scaling technology and economic factors, led to "large-scale integration" (LSI) by the mid-1970s, with tens of thousands of transistors per chip.

The masks used to process and manufacture SSI, MSI and early LSI and VLSI devices (such as the microprocessors of the early 1970s) were mostly created by hand, often using Rubylith-tape or similar. For large or complex ICs (such as memories or processors), this was often done by specially hired professionals in charge of circuit layout, placed under the supervision of a team of engineers, who would also, along with the circuit designers, inspect and verify the correctness and completeness of each mask.

Integrated circuits such as 1K-bit RAMs, calculator chips, and the first microprocessors, that began to be manufactured in moderate quantities in the early 1970s, had under 4,000 transistors. True LSI circuits, approaching 10,000 transistors, began to be produced around 1974, for computer main memories and second-generation microprocessors.

Very-large-scale integration (VLSI)

"Very-large-scale integration" (VLSI) is a development started with hundreds of thousands of transistors in the early 1980s, and, as of 2023, transistor counts continue to grow beyond 5.3 trillion transistors per chip.

Multiple developments were required to achieve this increased density. Manufacturers moved to smaller MOSFET design rules and cleaner fabrication facilities. The path of process improvements was summarized by the International Technology Roadmap for Semiconductors (ITRS), which has since been succeeded by the International Roadmap for Devices and Systems (IRDS). Electronic design tools improved, making it practical to finish designs in a reasonable time. The more energy-efficient CMOS replaced NMOS and PMOS, avoiding a prohibitive increase in power consumption. The complexity and density of modern VLSI devices made it no longer feasible to check the masks or do the original design by hand. Instead, engineers use EDA tools to perform most functional verification work.

In 1986, one-megabit random-access memory (RAM) chips were introduced, containing more than one million transistors. Microprocessor chips passed the million-transistor mark in 1989, and the billion-transistor mark in 2005. The trend continues largely unabated, with chips introduced in 2007 containing tens of billions of memory transistors.

ULSI, WSI, SoC and 3D-IC
To reflect further growth of the complexity, the term ULSI that stands for "ultra-large-scale integration" was proposed for chips of more than 1 million transistors.

Wafer-scale integration (WSI) is a means of building very large integrated circuits that uses an entire silicon wafer to produce a single "super-chip". Through a combination of large size and reduced packaging, WSI could lead to dramatically reduced costs for some systems, notably massively parallel supercomputers. The name is taken from the term Very-Large-Scale Integration, the current state of the art when WSI was being developed.

A system-on-a-chip (SoC or SOC) is an integrated circuit in which all the components needed for a computer or other system are included on a single chip. The design of such a device can be complex and costly, and whilst performance benefits can be had from integrating all needed components on one die, the cost of licensing and developing a one-die machine still outweigh having separate devices. With appropriate licensing, these drawbacks are offset by lower manufacturing and assembly costs and by a greatly reduced power budget: because signals among the components are kept on-die, much less power is required (see Packaging). Further, signal sources and destinations are physically closer on die, reducing the length of wiring and therefore latency, transmission power costs and waste heat from communication between modules on the same chip. This has led to an exploration of so-called Network-on-Chip (NoC) devices, which apply system-on-chip design methodologies to digital communication networks as opposed to traditional bus architectures.

A three-dimensional integrated circuit (3D-IC) has two or more layers of active electronic components that are integrated both vertically and horizontally into a single circuit. Communication between layers uses on-die signaling, so power consumption is much lower than in equivalent separate circuits. Judicious use of short vertical wires can substantially reduce overall wire length for faster operation.

Silicon labeling and graffiti
To allow identification during production, most silicon chips will have a serial number in one corner. It is also common to add the manufacturer's logo. Ever since ICs were created, some chip designers have used the silicon surface area for surreptitious, non-functional images or words. These are sometimes referred to as chip art, silicon art, silicon graffiti or silicon doodling.

ICs and IC families

 * The 555 timer IC
 * The Operational amplifier
 * 7400-series integrated circuits
 * 4000-series integrated circuits, the CMOS counterpart to the 7400 series (see also: 74HC00 series)
 * Intel 4004, generally regarded as the first commercially available microprocessor, which led to the 8008, the famous 8080 CPU, the 8086, 8088 (used in the original IBM PC), and the fully-backward compatible (with the 8088/8086) 80286, 80386/i386, i486, etc.
 * The MOS Technology 6502 and Zilog Z80 microprocessors, used in many home computers of the early 1980s
 * The Motorola 6800 series of computer-related chips, leading to the 68000 and 88000 series (the 68000 series was very successful and was used in the Apple Lisa and pre-PowerPC-based Macintosh, Commodore Amiga, Atari ST/TT/Falcon030, and NeXT families of computers, along with many models of workstations and servers from many manufacturers in the 80s, along with many other systems and devices)
 * The LM-series of analog integrated circuits

title: Integrated circuit


text:
IBM 3270

The IBM 3270 is a family of block oriented display and printer computer terminals introduced by IBM in 1971 and normally used to communicate with IBM mainframes. The 3270 was the successor to the IBM 2260 display terminal. Due to the text color on the original models, these terminals are informally known as green screen terminals. Unlike a character-oriented terminal, the 3270 minimizes the number of I/O interrupts required by transferring large blocks of data known as data streams, and uses a high speed proprietary communications interface, using coaxial cable.

IBM no longer manufactures 3270 terminals, but the IBM 3270 protocol is still commonly used via TN3270 clients, 3270 terminal emulation or web interfaces to access mainframe-based applications, which are sometimes referred to as green screen applications.

Principles
The 3270 series was designed to connect with mainframe computers, often at a remote location, using the technology then available in the early 1970s. The main goal of the system was to maximize the number of terminals that could be used on a single mainframe. To do this, the 3270 was designed to minimize the amount of data transmitted, and minimize the frequency of interrupts to the mainframe. By ensuring the CPU is not interrupted at every keystroke, a 1970s-era IBM 3033 mainframe fitted with only 16 MB of main memory was able to support up to 17,500 3270 terminals under CICS.

Most 3270 devices are clustered, with one or more displays or printers connected to a control unit (the 3275 and 3276 included an integrated control unit). Originally devices were connected to the control unit over coaxial cable; later Token Ring, twisted pair, or Ethernet connections were available. A local control unit attaches directly to the channel of a nearby mainframe. A remote control unit is connected to a communications line by a modem. Remote 3270 controllers are frequently multi-dropped, with multiple control units on a line.

IBM 3270 devices are connected to a 3299 multiplexer or to the cluster controller, e.g., 3271, 3272, 3274, 3174, using RG-62, 93 ohm, coax cables in a point to point configuration with one dedicated cable per terminal. Data is sent with a bit rate of 2.3587 Mbit/s using a slightly modified differential Manchester encoding. Cable runs of up to 1500 m are supported, although IBM documents routinely stated the maximum supported coax cable length was 2000 ft. Originally devices were equipped with BNC connectors, which later was replaced with special so-called DPC – Dual Purpose Connectors supporting the IBM Shielded twisted pair cabling system without the need for so-called red baluns.

In a data stream, both text and control (or formatting functions) are interspersed allowing an entire screen to be painted as a single output operation. The concept of formatting in these devices allows the screen to be divided into fields (clusters of contiguous character cells) for which numerous field attributes, e.g., color, highlighting, character set, protection from modification, can be set. A field attribute occupies a physical location on the screen that also determines the beginning and end of a field. There are also character attributes associated with individual screen locations.

Using a technique known as read modified, a single transmission back to the mainframe can contain the changes from any number of formatted fields that have been modified, but without sending any unmodified fields or static data. This technique enhances the terminal throughput of the CPU, and minimizes the data transmitted. Some users familiar with character interrupt-driven terminal interfaces find this technique unusual. There is also a read buffer capability that transfers the entire content of the 3270-screen buffer including field attributes. This is mainly used for debugging purposes to preserve the application program screen contents while replacing it, temporarily, with debugging information.

Early 3270s offered three types of keyboards. The typewriter keyboard came in both a 66 key version, with no programmed function (PF) keys, and a 78 key version with twelve. Both versions had two Program Attention (PA) keys. The data entry keyboard had five PF keys and two PA keys. The operator console keyboard had twelve PF keys and two PA keys. Later 3270s had an Attention key, a Cursor Select key, a System Request key, twenty-four PF keys and three PA keys. There was also a TEST REQ key. When one of these keys is pressed, it will cause its control unit to generate an I/O interrupt to the host computer and present an Attention ID (AID) identifying which key was pressed. Application program functions such as termination, page-up, page-down, or help can be invoked by a single key press, thereby reducing the load on very busy processors.

A downside to this approach was that vi-like behavior, responding to individual keystrokes, was not possible. For the same reason, a port of Lotus 1-2-3 to mainframes with 3279 screens did not meet with success because its programmers were not able to properly adapt the spreadsheet's user interface to a screen at a time rather than character at a time device. But end-user responsiveness was arguably more predictable with 3270, something users appreciated.

Applications
Following its introduction the 3270 and compatibles were by far the most commonly used terminals on IBM System/370 and successor systems. IBM and third-party software that included an interactive component took for granted the presence of 3270 terminals and provided a set of ISPF panels and supporting programs.

Conversational Monitor System (CMS) in VM has support for the 3270 continuing to z/VM.

Time Sharing Option (TSO) in OS/360 and successors has line mode command line support and also has facilities for full screen applications, e.g., ISPF.

Device independent Display Operator Console Support (DIDOCS) in Multiple Console Support (MCS) for OS/360 and successors supports 3270 devices and, in fact, MCS in current versions of MVS no longer supports line mode, 2250 and 2260 devices.

The SPF and Program Development Facility (ISPF/PDF) editors for MVS and VM/SP (ISPF/PDF was available for VM, but little used) and the XEDIT editors for VM/SP through z/VM make extensive use of 3270 features.

Customer Information Control System (CICS) has support for 3270 panels. Indeed, from the early 1970s on, CICS applications were often written for the 3270.

Various versions of Wylbur have support for 3270, including support for full-screen applications.

McGill University's MUSIC/SP operating system provided support for 3270 terminals and applications, including a full-screen text editor, a menu system, and a PANEL facility to create 3270 full-screen applications.

The modified data tag is well suited to converting formatted, structured punched card input onto the 3270 display device. With the appropriate programming, any batch program that uses formatted, structured card input can be layered onto a 3270 terminal.

IBM's OfficeVision office productivity software enjoyed great success with 3270 interaction because of its design understanding. And for many years the PROFS calendar was the most commonly displayed screen on office terminals around the world.

A version of the WordPerfect word processor ported to System/370 was designed for the 3270 architecture.

SNA
3270 devices can be a part of an SNA – System Network Architecture network or non-SNA network. If the controllers are SNA connected, they appear to SNA as PU – Physical Unit type 2.0 (PU2.1 for APPN) nodes typically with LU – Logical Unit type 1, 2, and 3 devices connected. Local, channel attached, controllers are controlled by VTAM – Virtual Telecommunications Access Method. Remote controllers are controlled by the NCP – Network Control Program in the Front End Processor i.e. 3705, 3720, 3725, 3745, and VTAM.

Third parties
One of the first groups to write and provide operating system support for the 3270 and its early predecessors was the University of Michigan, who created the Michigan Terminal System in order for the hardware to be useful outside of the manufacturer. MTS was the default OS at Michigan for many years, and was still used at Michigan well into the 1990s. Many manufacturers, such as GTE, Hewlett-Packard, Honeywell/Incoterm Div, Memorex, ITT Courier, McData, Harris, Alfaskop and Teletype/AT&T created 3270 compatible terminals, or adapted ASCII terminals such as the HP 2640 series to have a similar block-mode capability that would transmit a screen at a time, with some form validation capability. The industry distinguished between 'System compatible controllers' and 'Plug compatibility controllers', where 'System compatibility' meant that the 3rd party system was compatible with the 3270 data stream terminated in the unit, but not as 'Plug compatibility' equipment, also were compatible at the coax level thereby allowing IBM terminals to be connected to a 3rd party controller or vice versa. Modern applications are sometimes built upon legacy 3270 applications, using software utilities to capture (screen scraping) screens and transfer the data to web pages or GUI interfaces.

In the early 1990s a popular solution to link PCs with the mainframes was the Irma board, an expansion card that plugged into a PC and connected to the controller through a coaxial cable. 3270 simulators for IRMA and similar adapters typically provide file transfers between the PC and the mainframe using the same protocol as the IBM 3270 PC.

Models
The IBM 3270 display terminal subsystem consists of displays, printers and controllers. Optional features for the 3275 and 3277 are the selector-pen, ASCII rather than EBCDIC character set, an audible alarm, and a keylock for the keyboard. A keyboard numeric lock was available and will lock the keyboard if the operator attempts to enter non-numeric data into a field defined as numeric. Later an Operator Identification Card Reader was added which could read information encoded on a magnetic stripe card.

Displays
Generally, 3277 models allow only upper-case input, except for the mixed EBCDIC/APL or text keyboards, which have lower case. Lower-case capability and dead keys were available as an RPQ (Request Price Quotation); these were added to the later 3278 & 3279 models.

A version of the IBM PC called the 3270 PC, released in October 1983, includes 3270 terminal emulation. Later, the 3270 PC/G (graphics), 3270 PC/GX (extended graphics), 3270 Personal Computer AT, 3270 PC AT/G (graphics) and 3270 PC AT/GX (extended graphics) followed.

CUT vs. DFT
There are two types of 3270 displays in respect to where the 3270 data stream terminates. For CUT (Control Unit Terminal) displays, the stream terminates in the display controller, the controller instructs the display to move the cursor, position a character, etc. EBCDIC is translated by the controller into '3270 Character Set', and keyboard scan-codes from the terminal, read by the controller through a poll, is translated by the controller into EBCDIC. For DFT (Distributed Function Terminal) type displays, most of the 3270 data stream is forwarded to the display by the controller. The display interprets the 3270 protocol itself.

In addition to passing the 3270 data stream directly to the terminal, allowing for features like EAB — Extended Attributes, Graphics, etc., DFT also enabled multi sessions (up to 5 simultaneous), featured in the 3290 and 3194 multisession displays. This feature was also widely used in 2nd generation 3270 terminal emulation software.

The MLT — Multiple Logical Terminals feature of the 3174 controller also enabled multiple sessions from a CUT type terminal.

3277

 * 3277 model 1: 40×12 terminal
 * 3277 model 2: 80×24 terminal, the biggest success of all
 * 3277 GA: a 3277 with an RS232C I/O, often used to drive a Tektronix 4013 or 4015 graphic screen (monochrome)

3278

 * 3278 models 1–5: next-generation, with accented characters and dead keys in countries that needed them
 * model 1: 80x12
 * model 2: 80×24
 * model 2A: 80x24 (console) with 4 lines reserved
 * IBM 3278 and 3279 terminals.jpg 3: 80×32 or 80x24 (switchable)
 * model 4: 80×43 or 80x24 (switchable)
 * model 5: 132×27 or 80×24 (switchable)
 * Extended Highlighting: ability to set highlighting attributes on individual characters as well as on fields. For the 3278 that includes:
 * blinking
 * character set
 * reverse video
 * underscored
 * Programmed Symbols {PS): programmable characters; able to display monochrome graphics

The 3278, along with the 3279 color display and the 3287 printer, introduced the Extended Display Stream (EDS) as the framework for new features.

3279
The IBM 3279 was IBM's first color terminal. IBM initially announced four models, and later added a fifth model for use as a processor console.
 * Models
 * model 2A: 80-24 base color
 * model 2B: 80-24 extended color
 * model 2C: 80-24 base color (console) with 4 lines reserved
 * model 3A: 80-32 base color
 * model 3B: 80-32 extended color
 * Base color: In base color mode the protection and intensity field attributes determine the color:
 * {| class="wikitable"

! Protection ! Intensity ! Color
 * + Base color mode
 * Unprotected
 * Normal
 * style="color: Green;background-color:DarkGray; font-weight: bold;" | Green
 * Unprotected
 * Intensified
 * style="color: Red; background-color:DarkGray; font-weight: bold;" | Red
 * Protected
 * Normal
 * style="color: Blue; background-color:DarkGray; font-weight: bold;" | Blue
 * Protected
 * Intensified
 * style="color: White; background-color:DarkGray; font-weight: bold;" | White
 * }
 * Extended color: In extended color mode the color field and character attributes determine the color as one of
 * Neutral (White)
 * Red
 * Blue
 * Green
 * Pink
 * Yellow
 * Turquoise
 * Green
 * Pink
 * Yellow
 * Turquoise

The 3279 was introduced in 1979. The 3279 was widely used as an IBM mainframe terminal before PCs became commonly used for the purpose. It was part of the 3270 series, using the 3270 data stream. Terminals could be connected to a 3274 controller, either channel connected to an IBM mainframe or linked via an SDLC (Synchronous Data Link Control) link. In the Systems Network Architecture (SNA) protocol these terminals were logical unit type 2 (LU2). The basic models 2A and 3A used red, green for input fields, and blue and white for output fields. However, the models 2B and 3B supported seven colors, and when equipped with the optional Programmed Symbol Set feature had a loadable character set that could be used to show graphics.

The IBM 3279 with its graphics software support, Graphical Data Display Manager (GDDM), was designed at IBM's Hursley Development Laboratory, near Winchester, England.

3290
The 3290 Information Panel a 17", amber monochrome plasma display unit announced March 8, 1983, capable of displaying in various modes, including four independent 3278 model 2 terminals, or a single 160×62 terminal; it also supports partitioning. The 3290 supports graphics through the use of programmed symbols. A 3290 application can divide its screen area up into as many as 16 separate explicit partitions (logical screens).

The 3290 is a Distributed Function Terminal (DFT) and requires that the controller do a downstream load (DSL) of microcode from floppy or hard disk.

317x

 * 3178: lower cost terminal (1983)
 * 3179: low cost color terminal announced March 20, 1984.

3180
The 3180 was a monochrome display, introduced on March 20, 1984, that the user could configure for several different basic and extended display modes; all of the basic modes have a primary screen size of 24x80. Modes 2 and 2+ have a secondary size of 24x80, 3 and 3+ have a secondary size of 32x80, 4 and 4+ have a secondary size of 43x80 and 5 and 5+ have a secondary size of 27x132. An application can override the primary and alternate screen sizes for the extended mode. The 3180 also supported a single explicit partition that could be reconfigured under application control.

3191
The IBM 3191 Display Station is an economical monochrome CRT. Models A and B are 1920 characters 12-inch CRTs. Models D, E and L are 1920 or 2560 character 14-inch CRTs.

3192

 * Model C provides a 7-color 14 inch CRT with 80x24 or 80x32 characters
 * Model D provides a green monochrome 15 inch CRT with 80x24, 80x32, 80x44 or 132x27 characters
 * Model F provides a 7-color high-resolution 14 inch CRT with 80x24, 80x32, 80x44 or 132x27 characters
 * Model G provides a 7-color 14 inch CRT with 80x24 or 80x32 characters
 * Model L provides a green monochrome 15 inch CRT with 80x24, 80x32, 80x44 or 132x27 characters with a selector pen capability
 * Model W provides a black and while 15 inch CRT with 80x24, 80x32, 80x44 or 132x27 characters

3193
The IBM 3193 Display Station is a high-resolution, portrait-type, monochrome, 380mm (15 inch) CRT image display providing up to letter or A4 size document display capabilities in addition to alphanumeric data. Compressed images can be sent to the 3193 from a scanner and decompression is performed in the 3193. Image data compression is a technique to save transmission time and reduce storage requirements.

3194
The IBM 3194 is a Display Station that features a 1.44 MB 3.5" floppy drive and IND$FILE transfer.
 * Model C provides a 12-inch color CRT with 80x24 or 80x32 characters
 * Model D provides a 15-inch monochrome CRT with 80x24, 80x31, 80x44 or 132x27 characters
 * Model H provides a 14-inch color CRT with 80x24, 80x31, 80x44 or 132x27 characters

Subsequent

 * 3104: low-cost R-loop connected terminal for the IBM 8100 system
 * 3472 Infowindow

Non-IBM Displays
Several third-party manufacturers produced 3270 displays besides IBM.

GTE
GTE manufactured the IS/7800 Video Display System, nominally compatible with IBM 3277 displays attached to a 3271 or 3272. An incompatibility with the RA buffer order broke the logon screen in VM/SE (SEPP).

Harris
Harris manufactured the 8000 Series Terminal Systems, compatible with IBM 3277 displays attached to a 3271 or 3272.

Harris later manufactured the 9100–9200 Information Processing Systems, which included
 * 9178
 * 9278
 * 9279-2A
 * 9279-3G
 * 9280

Informer 270 376/SNA
Informer Computer Terminals manufactured a special version of their model 270 terminal that was compatible with IBM 3270 and its associated coax port to connect to a 3x74.

Memorex Telex
Attaches to 1371 or 1372
 * Memorex 1377, compatible with IBM 3277

Documentation for the following is available at

 * Memorex/Telex 2078
 * Memorex/Telex 2079
 * Memorex/Telex 2080
 * Memorex/Telex 2178
 * Memorex/Telex 2179

Nokia/Alfaskop

 * Alfaskop Display Unit 4110
 * Alfaskop Display Unit 4112

AT&T
AT&T introduced the Dataspeed 40 terminal/controller, compatible with the IBM 3275, in 1980.

Graphics models
IBM had two different implementations for supporting graphics. The first was implemented in the optional Programmed Symbol Sets (PSS) of the 3278, 3279 and 3287, which became a standard feature on the later 3279-S3G, a.k.a. 3279G, and was based on piecing together graphics with on-the-fly custom-defined symbols downloaded to the terminal.

The second later implementation provided All Points Addressable (APA) graphics, a.k.a. Vector Graphics, allowing more efficient graphics than the older technique. The first terminal to support APA / Vector graphics was the 3179G terminal that later was replaced by first the 3192G and later the 3472G.

Both implementations are supported by IBM GDDM — Graphical Data Display Manager first released in 1979, and by SAS with their SAS/GRAPH software.

IBM 3279G
IBM 3279-S3G, a.k.a. 3279G, terminal, announced in 1979, was IBM's graphics replacement for the 3279-3B with PSS. The terminal supported 7 colors and the graphics were made up of Programmable Symbol sets loaded to the terminal by the graphical application GDDM — Graphical Data Display Manager using Write Structured Field command.

Programmable Symbols is an addition to the normal base character set consisting of Latin characters, numbers, etc. hardwired into the terminal. The 3279G supports six additional sets of symbols each supporting 190 symbols, resulting in a total of 1.140 programmable symbols. Three of the Programmable Symbols sets have three planes each enabling coloring (red, blue, green) the Programmable Symbols downloaded to those sets, thereby supporting a total of seven colors.

Each 'character' cell consists of a 9x12 or a 9x16 dot matrix depending on the screen model. In order to program a cell with a symbol 18 bytes of data is needed making the data load quite heavy in some instances when compared to classic text screens.

If one for example wishes to draw a hyperbola on the screen, the application must first compute the required Programmable Symbols to make up hyperbola and load them to the terminal. The next step is then for the application to paint the screen by addressing the screen cell position and select the appropriate symbol in one of the Programmable Symbols sets.

The 3279G could be ordered with Attribute Select Keyboard enabling the operator to select attributes, colors and Programmable Symbols sets, making that version of the terminal quite distinctive.

IBM 3179G
The IBM 3179G announced June 18, 1985, is an IBM mainframe computer terminal providing 80×24 or 80×32 characters, 16 colors, plus graphics    and is the first terminal to support the APA graphics apart from the 3270 PC/G, 3270 PC/GX, PC AT/G and PC AT/GX.

3179-G terminals combine text and graphics as separate layers on the screen. Although the text and graphics appear combined on the screen, the text layer actually sits over the graphics layer. The text layer contains the usual 3270-style cells which display characters (letters, numbers, symbols, or invisible control characters). The graphics layer is an area of 720×384 pixels. All Points Addressable or vector graphics is used to paint each pixel in one of sixteen colors. As well as being separate layers on the screen, the text and graphics layers are sent to the display in separate data streams, making them completely independent.

The application i.e. GDDM sends the vector definitions to the 3179-G, and the work of activating the pixels that represent the picture (the vector-to-raster conversion) is done in the terminal itself. The datastream is related to the number of graphics primitives (lines, arcs, and so on) in the picture. Arcs are split into short vectors, that are sent to the 3179-G to be drawn. The 3179-G does not store graphic data, and so cannot offload any manipulation function from GDDM. In particular, with user control, each new viewing operation means that the data has to be regenerated and retransmitted.

The 3179G is a distributed function terminal (DFT) and requires a downstream load (DSL) to load its microcode from the cluster controller's floppy disk or hard drive.

The G10 model is a standard 122-key typewriter keyboard, while the G20 model offers APL on the same layout. Compatible with IBM System/370, IBM 4300 series, 303x, 308x, IBM 3090, and IBM 9370.

IBM 3192G
The IBM 3192G, announced in 1987 was the successor to 3179G. It featured 16 colors, and support for printers (i.e., IBM Proprinter) for local hardcopy with graphical support, or system printer, text only, implemented as an additional LU.

IBM 3472G
The IBM 3472G announced in 1989 was the successor to 3192G and featured five concurrent sessions, one of which could be graphics. Unlike the 3192-G, it needed no expansion unit to attach a mouse or color plotter, and it could also attach a tablet device for digitised input and a bar code reader.

APL / APL2
Most IBM terminals, starting with the 3277, could be delivered with an APL keyboard, allowing the operator/programmer to enter APL symbolic instructions directly into the editor. In order to display APL symbols on the terminal, it had to be equipped with an APL character set in addition to the normal 3270-character set. The APL character set is addressed with a preceding Graphic Escape X'08' instruction.

With the advent of the graphic terminal 3179G, the APL character set was expandable to 138 characters, called APL2. The added characters were: Diamond, Quad Null, Iota Underbar, Epsilon Underbar, Left Tack, Right Tack, Equal Underbar, Squished Quad, Quad Slope, and Dieresis Dot. Later APL2 symbols were supported by 3191 Models D, E, L, the CUT version of 3192, and 3472.

Please note that IBM's version's of APL also is called APL2.

Display-Controller

 * 3275 remote display with controller function (no additional displays up to one printer)
 * 3276 remote display with controller function. IBM 3276, announced in 1981, was a combined remote controller and display terminal, offering support for up to 8 displays, the 3276 itself included. By default, the 3276 had two type A coax ports, one for its own display, and one free for an additional terminal or printer. Up to three additional adapters, each supporting two coax devices, could be installed. The 3276 could connect to a non-SNA or SNA host using BSC or SDLC with line speed of up to 9,600 bit/s. The 3276 looked very much like the 3278 terminal, and the terminal feature of the 3276 itself, was more or less identical to those of the 3278.

Printers
In 1984 announced IPDS – Intelligent Printer Data Stream for online printing of AFP — Advanced Function Presentation documents, using bidirectional communications between the application and the printer. IPDS support among others printing of text, fonts, images, graphics, and barcodes. The IBM 4224 is one of the IPDS capable dot matrix printers.
 * 3284 matrix printer
 * 3286 matrix printer
 * 3287 printer, including a color model
 * 3288 line printer
 * 3268-1 R-loop connected stand-alone printer for the IBM 8100 system
 * 4224 matrix printer

With the emergence of printers, including laser printers, from HP, Canon, and others, targeted the PC market, 3270 customers got an alternative to IBM 3270 printers by connecting this type of printers through printer protocol converters from manufactures like I-data, MPI Tech, Adacom, and others. The printer protocol converters basically emulate a 3287 type printer, and later extended to support IPDS.

The IBM 3482 terminal, announced in 1992, offered a printer port, which could be used for host addressable printing as well as local screen copy.

In the later versions of 3174 the Asynchronous Emulation Adapter (AEA), supporting async RS-232 character-based type terminals, was enhanced to support printers equipped with a serial interface.

Controllers

 * 3271 remote controller
 * 3272 local controller
 * 3274 cluster controller (different models could be channel-attached or remote via BSC or SDLC communication lines, and had between eight and 32 co-ax ports)
 * 3174 cluster controller

On the 3274 and 3174, IBM used the term configuration support letter, sometimes followed by a release number, to designate a list of features together with the hardware and microcode needed to support them.

By 1994 the 3174 Establishment Controller supported features such as attachment to multiple hosts via Token Ring, Ethernet, or X.25 in addition to the standard channel attach or SDLC; terminal attachment via twisted pair, Token Ring or Ethernet in addition to co-ax; and TN3270. They also support attachment of asynchronous ASCII terminals, printers, and plotters alongside 3270 devices.

3274 controller
IBM introduced the 3274 controller family in 1977, replacing the 3271–2 product line.

Where the features of the 3271–2 was hardcoded, the 3274 was controlled by its microcode that was read from the 3274's built-in 8" floppy drive.

3274 models included 8, 12, 16, and 32 port remote controllers and 32-port local channel attached units. In total 16 different models were over time released to the market. The 3274-1A was an SNA physical Unit type 2.0 (PU2.0), required only a single address on the channel for all 32 devices and was not compatible with the 3272. The 3274-1B and 3274-1D were compatible with the 3272 and were referred to as local non-SNA models.

The 3274 controllers introduced a new generation of the coax protocol, named Category A, to differentiate them from the Category B coax devices, such as the 3277 terminal and the 3284 printer. The first Category A coax devices were the 3278 and the first color terminal, the IBM 3279 Color Display Station.

Enabling backward compatibility, it was possible to install coax boards, so-called 'panels', in groups of 4 or 8 supporting the now older Category B coax devices. A maximum of 16 Category B terminals could be supported, and only 8 if the controller were fully loaded with a maximum of 4 panels each supporting 8 Category A devices.

During its life span, the 3274 supported several features including:

 * Extended Data Stream
 * Extended Highlighting
 * Programmed Symbol Set (PSS)
 * V.24 interfaces with speed up to 14.4 kbit/s
 * V.35 interfaces with speed up to 56 kbit/s
 * X.25 network attachment
 * DFT – Distributed Function Terminal
 * DSL – Downstream load for 3290 and 3179G
 * 9901 and 3299 multiplexer
 * Entry Assist
 * Dual Logic (the feature of having two sessions from a CUT mode display).

3174 controller
IBM introduced the 3174 Subsystem Control Unit in 1986, replacing the 3274 product line.

The 3174 was designed to enhance the 3270 product line with many new connectivity options and features. Like the 3274, it was customizable, the main difference was that it used smaller (5.25-inch) diskettes than the 3274 (8-inch diskettes), and that the larger floor models had 10 slots for adapters, some of them were per default occupied by channel adapter/serial interface, coax adapter, etc. Unlike the 3274, any local models could be configured as either local SNA or local non-SNA, including PU2.1 (APPN).

The models included: 01L, 01R, 02R, 03R, 51R, 52R, 53R, 81R and 82R.

The 01L were local channel attached, the R models remotely connected, and the x3R Token Ring (upstream) connected. The 0xL/R models were floor units supporting up to 32 coax devices through the use of internal or external multiplexers (TMA/3299). The 5xR, models were shelf units with 9 coax ports, expandable to 16, by the connection of a 3299 multiplexer. The smallest desktop units, 8xR, had 4 coax ports expandable to 8, by the connection of a 3299 multiplexer.

In the 3174 controller line IBM also slightly altered the classical BNC coax connector by changing the BNC connector to DPC – Dual Purpose Connector. The DPC female connector was a few millimeters longer and with a built-in switch that detected if a normal BNC connector were connected or a newer DPC connector was connected, thereby changing the physical layer from 93 ohm unbalanced coax, to 150 ohm balanced twisted-pair, thereby directly supporting the IBM Cabling system without the need for a so-called red balun.

Configuration Support A was the first microcode offered with the 3174. It supported all the hardware modules present at the time, almost all the microcode features found in 3274 and introduced a number of new features including: Intelligent Printer Data Stream (IPDS), Multiple Logical Terminals, Country Extended Code Page (CECP), Response Time Monitor, and Token Ring configured as host interface.

Configuration Support S, strangely following release A, introduced that a local or remote controller could act as 3270 Token-Ring DSPU Gateway, supporting up to 80 Downstream PU's.

In 1989, IBM introduced a new range of 3174 models and changed the name from 3174 Subsystem Control Unit to 3174 Establishment Controller. The main new feature was support for an additional 32 coax port in floor models.

The models included: 11L, 11R, 12R, 13R, 61R, 62R, 63R, 91R, and 92R.

The new line of controllers came with Configuration Support B release 1, increased the number of supported DSPU on the Token-Ring gateway to 250 units, and introduced at the same time 'Group Polling' that offloaded the mainframe/VTAM polling requirement on the channel.

Configuration Support B release 2 to 5, enabled features like: Local Format Storage (CICS Screen Buffer), Type Ahead, Null/Space Processing, ESCON channel support.

In 1990–1991, a total of 7 more models were added: 21R, 21L, 12L, 22L, 22R, 23R, and 90R. The 12L offered ESCON fibreoptic channel attachment. The models with 2xx designation were equal to the 1xx models but repacked for rackmount and offered only 4 adapter slots. The 90R was not intended as a coax controller, it was positioned as a Token Ring 3270 DSPU gateway. However, it did have one coax port for configuring the unit, which with a 3299 multiplexer could be expanded to 8.

The line of controllers came with Configuration Support C to support ISDN, APPN and Peer Communication. The ISDN feature allowed downstream devices, typically PC's, to connect to the 3174 via the ISDN network. The APPN support enabled the 3174 to be a part of an APPN network, and the Peer Communication allowed coax attached PC's with 'Peer Communication Support' to access resources on the Token-Ring network attached to the 3174.

The subsequent releases 2 to 6 of Configuration Support C enables support for: Split screen, Copy from session to session, Calculator function, Access to AS/400 host and 5250 keyboard emulation, Numerous APPN enhancements, TCP/IP Telnet support that allowed 3270 CUT terminals to communicate with TCP/IP servers using Telnet, and at the same time in another screen to communicate with the mainframe using native 3270. TN3270 support where the 3174 could connect to a TN3270 host/gateway, eliminating SNA, but preserving the 3270 data stream. IP forwarding allowing bridging of LAN (Token-Ring or Ethernet) connected devices downstream to the 3174 to route IP traffic onto the Frame Relay WAN interface.

In 1993, three new models were added with the announcement of Ethernet Adapter (FC 3045). The models were: 14R, 24R, and 64R.

This was also IBM's final hardware announcement of 3174.

The floor models, and the rack-mountable units, could be expanded with a range of special 3174 adapters, that by 1993 included: Channel adapter, ESCON adapter, Serial (V.24/V.35) adapter, Concurrent Communication Adapter, Coax adapter, Fiber optic "coax" adapter, Async adapter, ISDN adapter, Token-Ring adapter, Ethernet adapter, and line encryption adapter.

In 1994, IBM incorporated the functions of RPQ 8Q0935 into Configuration Support-C release 3, including the TN3270 client.

GTE
The GTE IS/7800 Video Display Systems used one of two nominally IBM compatible controllers:

 * 7801 (remote, 3271 equivalent)
 * 7802 (local, 3277 equivalent)

Harris
The Harris 8000 Series Terminal Systems used one of four controllers:

 * 8171 (remote, 3271 equivalent)
 * 8172 (local, 3277 equivalent)
 * 8181 (remote, 3271 equivalent)
 * 8182 (local, 3277 equivalent)
 * 9116
 * 9210
 * 9220

Home grown
An alternative implementation of an establishment controller exists in form of OEC (Open Establishment Controller). It's a combination of an Arduino shield with a BNC connector and a Python program that runs on a POSIX system. OEC allows to connect a 3270 display to IBM mainframes via TN3270 or to other systems via VT100. Currently only CUT but not DFT displays are supported.

Memorex
Memorex had two controllers for its 3277-compatible 1377; the 1371 for remote connection and the 1372 for local connection.

Later Memorex offered a series of controllers compatible with the IBM 3274 and 3174

 * 2074
 * 2076
 * 2174
 * 2274

Multiplexers
IBM offered a device called 3299 that acted as a multiplexer between an accordingly configured 3274 controller, with the 9901 multiplexer feature, and up to eight displays/printers, thereby reducing the number of coax cables between the 3x74 controller and the displays/printers.

With the introduction of the 3174 controller internal or external multiplexers (3299) became mainstream as the 3174-1L controller was equipped with four multiplexed ports each supporting eight devices. The internal 3174 multiplexer card was named TMA – Terminal Multiplexer adapter 9176.

A number of vendors manufactured 3270 multiplexers before and alongside IBM including Fibronics and Adacom offering multiplexers that supported TTP – Telephone Twisted Pair as an alternative to coax, and fiber-optic links between the multiplexers.

In some instances, the multiplexer worked as an "expansion" unit on smaller remote controllers including the 3174-81R / 91R, where the 3299 expanded the number of coax ports from four to eight, or the 3174-51R / 61R, where the 3299 expanded the number of coax ports from eight to 16.

Manufacture
The IBM 3270 display terminal subsystem was designed and developed by IBM's Kingston, New York, laboratory (which later closed during IBM's difficult time in the mid-1990s). The printers were developed by the Endicott, New York, laboratory. As the subsystem expanded, the 3276 display-controller was developed by the Fujisawa laboratory, Japan, and later the Yamato laboratory; and the 3279 color display and 3287 color printer by the Hursley, UK, laboratory. The subsystem products were manufactured in Kingston (displays and controllers), Endicott (printers), and Greenock, Scotland, UK, (most products) and shipped to users in U.S. and worldwide. 3278 terminals continued to be manufactured in Hortolândia, near Campinas, Brazil as far as late 1980s, having its internals redesigned by a local engineering team using modern CMOS technology, while retaining its external look and feel.

Telnet 3270
Telnet 3270, or tn3270 describes both the process of sending and receiving 3270 data streams using the telnet protocol and the software that emulates a 3270 class terminal that communicates using that process. tn3270 allows a 3270 terminal emulator to communicate over a TCP/IP network instead of an SNA network. Telnet 3270 can be used for either terminal or print connections. Standard telnet clients cannot be used as a substitute for tn3270 clients, as they use fundamentally different techniques for exchanging data.

3270 character set
The 3270 displays are available with a variety of keyboards and character sets. The following table shows the 3275/3277/3284–3286 character set for US English EBCDIC (optional characters were available for US ASCII, and UK, French, German, and Italian EBCDIC).

On the 3275 and 3277 terminals without the a text feature, lower case characters display as uppercase. NL, EM, DUP, and FM control characters display and print as 5, 9, *, and ; characters, respectively, except by the printer when WCC or CCC bits 2 and 3 = '00'b, in which case NL and EM serve their control function and do not print.

Data stream
Data sent to the 3270 consist of commands, a Copy Control Character (CCC) or Write Control Character (WCC) if appropriate, a device address for copy, orders, character data and structured fields. Commands instruct the 3270 control unit to perform some action on a specified device, such as a read or write. Orders are sent as part of the data stream to control the format of the device buffer. Structured fields are to convey additional control functions and data to or from the terminal.

On a local non-SNA controller, the command is a CCW opcode rather than the first byte of the outbound display stream; on all other controllers, the command is the first byte of the display stream, exclusive of protocol headers.

Commands
The following table includes datastream commands and CCW opcodes for local non-SNA controllers; it does not include CCW opcodes for local SNA controllers.

Write control character
The data sent by Write or Erase/Write consists of the command code itself followed by a Write Control Character (WCC) optionally followed by a buffer containing orders or data (or both). The WCC controls the operation of the device. Bits may start printer operation and specify a print format. Other bit settings will sound the audible alarm if installed, unlock the keyboard to allow operator entry, or reset all the Modified Data Tags in the device buffer.

Orders
Orders consist of the order code byte followed by zero to three bytes of variable information.

Attributes
The 3270 has three kinds of attributes:
 * Field attributes
 * Extended attributes
 * Character attributes

Field attributes
The original 3277 and 3275 displays used an 8-bit field attribute byte of which five bits were used.
 * Bits 0 and 1 are set so that the attribute will always be a valid EBCDIC (or ASCII) character.
 * Bit 2 is zero to indicate that the associated field is unprotected (operator could enter data) or one for protected.
 * Bit 3 is zero to indicate that this field, if unprotected, could accept alphanumeric input. One indicates that only numeric input is accepted, and automatically shifts to numeric for some keyboards.
 * Bit 4 and 5 operate in tandem:
 * '00'B indicate that the field is displayed on the screen and is not selector-pen detectable.
 * '01'B indicates that the field is displayable and selector-pen detectable.
 * '10'B indicates that the field is intensified (bright), displayable, and selector-pen detectable.
 * '11'B indicates that the field is non-display, non-printable, and not pen detectable. This last can be used in conjunction with the modified data tag to imbed static data on the screen that will be read each time data was read from the device.
 * Bit 7 is the "Modified Data Tag", where '0' indicates that the associated field has not been modified by the operator and '1' indicates that it has been modified. As noted above, this bit can be set programmatically to cause the field to be treated as modified.

Later models include base color: "Base color (four colors) can be produced on color displays and color printers from current 3270 application programs by use of combinations of the field intensify and field protection attribute bits. For more information on color, refer to IBM 3270 Information System: Color and Programmed Symbols, GA33-3056."

Extended attributes
The 3278 and 3279 and later models used extended attributes to add support for seven colors, blinking, reverse video, underscoring, field outlining, field validation, and programmed symbols.

Character attributes
The 3278 and 3279 and later models allowed attributes on individual characters in a field to override the corresponding field attributes.

This allowed programs (such as the LEXX text editor) to assign any font (including the programmable fonts), colour, etc. to any character on the screen.

Buffer addressing
3270 displays and printers have a buffer containing one byte for every screen position. For example, a 3277 model 2 featured a screen size of 24 rows of 80 columns for a buffer size of 1920 bytes. Bytes are addressed from zero to the screen size minus one, in this example 1919. "There is a fixed relationship between each ... buffer storage location and its position on the display screen." Most orders start operation at the "current" buffer address, and executing an order or writing data will update this address. The buffer address can be set directly using the Set Buffer Address (SBA) order, often followed by Start Field or Start Field Extended. For a device with a 1920 character display a twelve bit address is sufficient. Later 3270s with larger screen sizes use fourteen or sixteen bits.

Addresses are encoded within orders in two bytes. For twelve bit addresses the high order two bits of each byte are set to form valid EBCDIC (or ASCII) characters. For example, address 0 is coded as X'4040', or space-space, address 1919 is coded as X'5D7F', or '"'. Programmers hand-coding panels usually keep the table of addresses from the 3270 Component Description or the 3270 Reference Card handy. For fourteen and sixteen-bit address, the address uses contiguous bits in two bytes.

Example
The following data stream writes an attribute in row 24, column 1, writes the (protected) characters '> ' in row 24, columns 2 and 3, and creates an unprotected field on row 24 from columns 5-79. Because the buffer wraps around an attribute is placed on row 24, column 80 to terminate the input field. This data stream would normally be written using an Erase/Write command which would set undefined positions on the screen to '00'x. Values are given in hexadecimal. Data       Description D3         WCC [reset device + restore (unlock) keyboard + reset MDT] 11 5C F0   SBA Row 24 Column 1 1D F0      SF/Attribute [protected, alphanumeric, display normal intensity, not pen-detectable, MDT off] 6E 40      '> ' 1D 40      SF/Attribute [unprotected, alphanumeric, display normal intensity, not pen-detectable, MDT off] SBA is not required here since this is being written at the current buffer position 13         IC — cursor displays at current position: Row 24, column 5 11 5D 7F   SBA Row 24 Column 80 1D F0      SF/Attribute [protected, alphanumeric, display normal intensity, not pen-detectable, MDT off]

Extended Data Stream
Most 3270 terminals newer than the 3275, 3277, 3284 and 3286 support an extended data stream (EDS) that allows many new capabilities, including:
 * Display buffers larger than 4096 characters
 * Additional field attributes, e.g., color
 * Character attributes within a field
 * Redefining display geometry
 * Querying terminal characteristics
 * Programmed Symbol Sets
 * All Points Addressable (APA) graphics

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title: IBM 3270