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 signal the ...

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 type ...

, in order to increase the area available for computer programs running on a single

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

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

Implementation

Analog Monitor Splitter (unbranded)-2312

Multiple computers can be connected to provide a single display, e.g. over Gigabit Ethernet/ Ethernet to drive a large video wall.

Display modes

USB

One way to extend the number of displays on one computer is to add displays via USB. Starting in 2006,

DisplayLink DisplayLink (formerly Newnham Research) is a semiconductor and software technology company. They develop the DisplayLink USB graphics technology, which is designed to connect computers and displays using USB, Ethernet, and WiFi. It also allow ...

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'' and '' World of Warcraft'' 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's '' Ridge Racer'' 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 multinational corporation, multinational video game and entertainment company headquartered in Shinagawa, Tokyo. Its international branches, Sega of America and Sega Europe, are headquartered in Irvine, California and London, r ...

'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, Japan. It develops video games and video game consoles. Nintendo was founded in 1889 as by craftsman Fusajiro Yamauchi and originally produce ...

demonstrated the feasibility of playing multi-monitor games on handheld game consoles in designing the

Nintendo DS The is a 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 working in tan ...

and its successor, the

Nintendo 3DS The is a handheld game console produced by Nintendo. It was announced in March 2010 and unveiled at E3 2010 as the successor to the Nintendo DS. The system features backward compatibility with Nintendo DS video games. As an eighth-generatio ...

, 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.

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 Android may refer to: Science and technology * Android (robot), a humanoid robot or synthetic organism designed to imitate a human * Android (operating system), Google's mobile operating system ** Bugdroid, a Google mascot sometimes referred to ...

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 visual display, support electronics, power supply, housing, electrical connectors, and external user controls. The di ...

to having multiple technical features such as a touchscreen,

web cam A webcam is a video camera which is designed to record or stream to a computer or computer network. They are primarily used in videotelephony, livestreaming and social media, and security. Webcams can be built-in computer hardware or peripheral de ...

or even a barcode reader 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 Dual input or dual point user input are common terms describing the 'multiple touch input on two devices simultaneously' challenge. When there are touch input commands from two touch monitors simultaneously this will require a technical soluti ...

. In 2017 LG unsuccessfully tried to copyright the term “second display”, meaning that it is available for everyone to use freely.

Professional meaning

Shop and IT-support staff can use the term “second display” when referring to the second monitor in a multi-monitor setup. Second display på McCafé

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 and hotel 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, 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 (CRM) system.