Multi-monitor, also called multi-display and multi-head, is the use of multiple physical

display device A display device is an output device for presentation of information in visual or tactile form (the latter used for example in tactile electronic displays for blind people). When the input information that is supplied has an electrical signa ...

s, such as monitors, televisions, and

projectors A projector or image projector is an optical device that projects an image (or moving images) onto a surface, commonly a projection screen. Most projectors create an image by shining a light through a small transparent lens, but some newer typ ...

, in order to increase the area available for

computer program A computer program is a sequence or set of instructions in a programming language for a computer to Execution (computing), execute. It is one component of software, which also includes software documentation, documentation and other intangibl ...

s running on a single

computer A computer is a machine that can be Computer programming, programmed to automatically Execution (computing), carry out sequences of arithmetic or logical operations (''computation''). Modern digital electronic computers can perform generic set ...

system. Research studies show that, depending on the type of work, multi-head may increase the productivity by between 50 and 70 percent.

Implementation

Multiple computers can be connected to provide a single display, e.g. over

Gigabit Ethernet In computer networking, Gigabit Ethernet (GbE or 1 GigE) is the term applied to transmitting Ethernet frames at a rate of a gigabit per second. The most popular variant, 1000BASE-T, is defined by the IEEE 802.3ab standard. It came into use in ...

Ethernet Ethernet ( ) is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in 198 ...

to drive a large

video wall A video wall is a special multi-monitor setup that consists of multiple computer monitors, video projectors, or television sets tiled together contiguously or overlapped in order to form one large screen. Typical display technologies include ...

Studies and safety

Measurements of the Institute for Occupational Safety and Health of the German Social Accident Insurance showed that the quality and quantity of worker performance varies according to the screen setup and type of task. Overall, the results of physiological studies and the preferences of the test persons favour a dual-monitor rather than single-monitor setup. Physiologically limiting factors observed during work on dual monitors were minor and not generally significant. There is no evidence that office work with dual-monitor setups presents a possible hazard to workers.

Display modes

USB

One way to extend the number of displays on one computer is to add displays via USB. Starting in 2006, DisplayLink released several chips for USB support on VGA/DVI/LVDS and other interfaces.

Adoption

In the office

2012 Bloomberg Terminal by jm3 - Creative Commons licensed

In many professions, including graphic design, architecture, communications, accounting, engineering and video editing, the idea of two or more monitors being driven from one machine is not a new one. While in the past, it has meant multiple graphics adapters and specialized software, it was common for engineers to have at least two, if not more, displays to enhance productivity.

In video gaming

Early versions of '' Doom'' permitted a three-monitor display mode, using three networked machines to show left, right, and center views. More recently, games have used multiple monitors to show a more absorbing interface to the player or to display game information. Various flight simulators can use these monitor setups to create an artificial cockpit with more realistic interfaces. Others such as '' Supreme Commander'' and '' World in Conflict'' can use an additional monitor for a large scale map of the battlefield. A large number of older games support multi-monitor set-ups by treating the total screen space as effectively a single monitor to the game, a technique known as spanning. Many games without inherent multi-monitor support such as ''

Guild Wars ''Guild Wars'' is an online role-playing game franchise developed by ArenaNet and published by NCSoft. The games were critically well received and won many editor's choice awards, as well as awards such as "D.I.C.E. Award for Role-Playing Game ...

'' and ''

World of Warcraft ''World of Warcraft'' (''WoW'') is a 2004 massively multiplayer online role-playing (MMORPG) video game developed and published by Blizzard Entertainment for Windows and Mac OS X. Set in the '' Warcraft'' fantasy universe, ''World of War ...

'' can also be made to run in multi-monitor set-ups, with this technique or in conjunction with addition of third-party software A larger list of games that support dual/multi-screen modes is available at WSGF.

Arcade machines and handheld console games

The concept of "multi-monitor" games is not limited to games that can be played on personal computers. As arcade technology entered the 1990s, larger cabinets were being built which in turn also housed larger monitors such as the 3 28" screen version of

Namco was a Japanese multinational video game and entertainment company founded in 1955. It operated video arcades and amusement parks globally, and produced video games, films, toys, and arcade cabinets. Namco was one of the most influential c ...

's ''

Ridge Racer is a series of racing video games created by Namco and owned by Bandai Namco Entertainment. The first game, ''Ridge Racer (1993 video game), Ridge Racer'' (1993), was originally released in arcades for the Namco System 22 hardware, later ported ...

'' from 1993. Although large screen technology such as CRT rear projection was beginning to be used more often, multi-monitor games were still occasionally released, such as

Sega is a Japanese video game company and subsidiary of Sega Sammy Holdings headquartered in Tokyo. It produces several List of best-selling video game franchises, multi-million-selling game franchises for arcade game, arcades and video game cons ...

's '' F355 Challenge'' from 1999 which again used 3 28" monitors for the sit-down cockpit version. The most recent use of a multi-monitor setup in arcades occurred with Taito's ''Dariusburst: Another Chronicle'' game, released in Japan in December 2010 and worldwide the following year. It uses 2 32" LCD screens and an angled mirror to create a seamless widescreen.

Nintendo is a Japanese Multinational corporation, multinational video game company headquartered in Kyoto. It develops, publishes, and releases both video games and video game consoles. The history of Nintendo began when craftsman Fusajiro Yamauchi ...

demonstrated the feasibility of playing multi-monitor games on

handheld game consoles A handheld game console, or simply handheld console, is a small, portable self-contained video game console with a built-in screen, game controls and speakers. Handheld game consoles are smaller than home video game consoles and contain the con ...

in designing the

Nintendo DS The is a foldable handheld game console produced by Nintendo, released globally across 2004 and 2005. The DS, an initialism for "Developers' System" or "Dual Screen", introduced distinctive new features to handheld games: two LCD screens worki ...

and its successor, the

Nintendo 3DS The is a foldable dual-screen handheld game console produced by Nintendo. Announced in March 2010 as the successor to the Nintendo DS, the console was released originally on February 26, 2011 and went through various revisions in its lifetime, ...

, which both became successful consoles in their own right. Games on these systems take advantage of the two screens available, typically by displaying gameplay on the upper screen, while showing useful information on the bottom screen. There are also a number of games, mostly for the Nintendo DS, whose gameplay spans across both screens, combining them into one tall screen for a more unique and larger view of the action.

Vertical monitor

Vertical monitors are usually added as a secondary display to the left or right of the main landscape oriented monitor. They are useful to display more information vertically down the page, computer programmers use this configuration most often to see as many lines of code on the screen as possible without having to scroll a lot.

Developing software for multiple monitor workstations

Ordinary software does not need special support for multiple screens even if it uses the graphic accelerator. At the usual application level, multihead is presented just as a single larger monitor spanning over all screens. However, some special approaches may increase the multithread performance. With multiple monitors present, each screen will have its own graphics buffer. One possible scenario for programming is to present to OpenGL or DirectX a continuous, virtual frame buffer in which the OS or graphics driver writes out to each individual buffer. With some graphics cards, it's possible to enable a mode called "horizontal span" which accomplishes this. The OpenGL/DirectX programmer then renders to a very large frame buffer for output. In practice, and with recent cards, this mode is being phased out because it does not make very good use of GPU parallelism and does not support arbitrary arrangements of monitors (they must all be horizontal). A more recent technique uses the wglShareLists feature of OpenGL to share data across multiple GPUs, and then render to each individual monitor's frame buffer.

In Android

Android supports an additional monitor as of version 4.2 but additional software is needed to multi-task/use both at once.

Second displays

A second display or second displays is a common term describing the multi-monitor setup with just one additional monitor attached. Today it is particularly common to have one workstation with two monitors connected where the second monitor is referred to as the second display. Many tablets will serve as a second display connected to a laptop. Many modern shops use cash registers with two screens, one facing the cashier and a second display facing the shopper. Today's second display has evolved from a multi screen personal

computer monitor A computer monitor is an output device that displays information in pictorial or textual form. A discrete monitor comprises a electronic visual display, visual display, support electronics, power supply, Housing (engineering), housing, electri ...

to having multiple technical features such as a

touchscreen A touchscreen (or touch screen) is a type of electronic visual display, display that can detect touch input from a user. It consists of both an input device (a touch panel) and an output device (a visual display). The touch panel is typically l ...

, web cam or even a

barcode reader A barcode reader or barcode scanner is an optical scanner that can read printed barcodes and send the data they contain to computer. Like a flatbed scanner, it consists of a light source, a lens, and a light sensor for translating optical impul ...

in stores. When a simultaneous touch input is performed on two devices simultaneously there will be a technical solution required to solve the dual input. The

European Union Intellectual Property Office The European Union Intellectual Property Office (EUIPO) () is a decentralised agency of the EU responsible for the registration of EU-wide unitary trade marks and industrial design rights. These exist alongside the intellectual property rig ...

rejected a

trademark A trademark (also written trade mark or trade-mark) is a form of intellectual property that consists of a word, phrase, symbol, design, or a combination that identifies a Good (economics and accounting), product or Service (economics), service f ...

application for "second display" by

LG Electronics LG Electronics Inc. () is a South Korean Multinational corporation, multinational major appliance and consumer electronics corporation headquartered in Yeouido-dong, Seoul, South Korea. LG Electronics is a part of LG, LG Corporation, the fourth ...

, citing that the term was not distinctive.

Professional meaning

Shop and IT-support staff can use the term “second display” when referring to the second monitor in a multi-monitor setup. Retail and hotel businesses have a professional meaning for a "second display", also known as interactive customer display or dual-screen for shops. The term is used in

retail Retail is the sale of goods and services to consumers, in contrast to wholesaling, which is the sale to business or institutional customers. A retailer purchases goods in large quantities from manufacturers, directly or through a wholes ...

and

hotel A hotel is an establishment that provides paid lodging on a short-term basis. Facilities provided inside a hotel room may range from a modest-quality mattress in a small room to large suites with bigger, higher-quality beds, a dresser, a re ...

environments when referring to a customer facing display that is connected to the

point of sale The point of sale (POS) or point of purchase (POP) is the time and place at which a retail transaction is completed. At the point of sale, the merchant calculates the amount owed by the customer, indicates that amount, may prepare an invoice f ...

(POS) system. Normally a second display solution contains both hardware and interactive software allowing the shopper to perform certain actions. The second display is most commonly used to show the total purchase amount and the purchase list. Some advanced systems contain functionality relating to loyalty and member data. In an article from 2021 the Swedish retail magazine Dagens Handel mentions the provider of second displays ID24 and their published survey among retail and hospitality companies. The second display can draw shoppers' attention to new products,

advertisements Advertising is the practice and techniques employed to bring attention to a product or service. Advertising aims to present a product or service in terms of utility, advantages, and qualities of interest to consumers. It is typically us ...

, charities, or special offers. The displays can also be used for different kinds of user input – for example entering an email to receive an electronic receipt, give feedback or sign up for loyalty to the

customer relationship management Customer relationship management (CRM) is a strategic process that organizations use to manage, analyze, and improve their interactions with customers. By leveraging data-driven insights, CRM helps businesses optimize communication, enhance cus ...

(CRM) system.