View source for Single-board computer

{{distinguish|Microcomputer}}
{{short description|Computer whose components are on a single printed circuit board}}
{{multiple issues|
{{more citations needed|date=December 2022}}
{{Update|date=June 2022}}
}}

[[File:Raspberry-Pi-2-Bare-BR.jpg|thumb|The [[Raspberry Pi]] (Model 2B shown) is a low-cost single-board computer often used to teach [[computer science]].<ref name="raspi-foundation">{{cite web|title=Foundation Strategy 2016–2018|url=https://www.raspberrypi.org/files/about/RaspberryPiFoundationStrategy2016-18.pdf|website=Raspberry Pi|publisher=Raspberry Pi Foundation|access-date=26 November 2016|pages=3–5|archive-date=9 June 2016|archive-url=https://web.archive.org/web/20160609120805/https://www.raspberrypi.org/files/about/RaspberryPiFoundationStrategy2016-18.pdf|url-status=live}}</ref>]]

A '''single-board computer''' ('''SBC''') is a complete [[computer]] built on a single [[circuit board]], with [[microprocessor]](s), [[random-access memory|memory]], [[input/output]] (I/O) and other features required of a functional computer. Single-board computers are commonly made as demonstration or development systems, for educational systems, or for use as [[embedded system|embedded computer controllers]]. Many types of [[home computer]]s or [[portable computer]]s integrate all their functions onto a single [[printed circuit board]].

Unlike a desktop [[personal computer]], single-board computers often do not rely on [[expansion slot]]s for peripheral functions or [[expansion card|expansion]]. Single-board computers have been built using a wide range of [[microprocessor]]s. Simple designs, such as those built by computer hobbyists, often use [[static RAM]] and low-cost [[32-bit|32]]- or [[64-bit]] processors like [[ARM processor|ARM]]. Other types, such as [[blade server]]s, would perform similar to a [[server (computing)|server]] computer, only in a more compact format.

A [[computer-on-module]] is a type of single-board computer made to plug into a carrier board, baseboard, or [[backplane]] for system expansion.<ref name="com-sbcs">{{cite web|title=COM – Based SBCs: The Superior Architecture for Small Form Factor Embedded Systems|url=http://whitepaper.opsy.st/WhitePaper.diamondsys-combased-sbcs-wpfinal-.pdf|publisher=Diamond Systems Corp.|access-date=27 December 2016|archive-date=29 December 2016|archive-url=https://web.archive.org/web/20161229031021/http://whitepaper.opsy.st/WhitePaper.diamondsys-combased-sbcs-wpfinal-.pdf|url-status=live}}</ref><ref>{{cite web|title=Implementing High Performance Embedded Computing Hardware|url=http://www.trentonsystems.com/wp-content/uploads/Implementing-High-Performance-Embedded-Computing-Hardware.pdf|publisher=Trenton Systems, Inc.|access-date=26 November 2016|pages=13–15|date=September 1, 2016|archive-date=26 November 2016|archive-url=https://web.archive.org/web/20161126133745/http://www.trentonsystems.com/wp-content/uploads/Implementing-High-Performance-Embedded-Computing-Hardware.pdf|url-status=live}}</ref>

==History==
{{llm|section|date=July 2025}}
[[Image:Early 1976 MMD1 Prototype most chips removed.JPG|thumb|An early MMD-1, the world's first true single-board computer, with most chips removed]]
The first true single-board computer was based on the Intel [[Intel 8080|C8080A]], also using Intel's first [[EPROM]], the C1702A. Schematics for the machine, called the "dyna-micro" were published in ''[[Radio-Electronics]]'' magazine in May 1976. Later that year, production of the system began by E&L Instruments, a [[Derby, Connecticut]]-based computer manufacturer, which branded the system as the "Mini Micro Designer 1", intending it for use as a [[Microcontroller|programmable microcontroller]] for prototyping electronic products.<ref>{{Cite web |title=E&L Instruments {{!}} OpenCorporates |url=https://opencorporates.com/companies/us_ct/0014522 |access-date=2023-03-06 |website=opencorporates.com}}</ref><ref>{{Cite web |title=Mini-Micro Designer 1 (MMD1) |url=http://www.decodesystems.com/mmd1.html |access-date=2023-03-06 |website=www.decodesystems.com}}</ref> The MMD-1 was made famous as an example [[microcomputer]] in popular 8080 instruction series of the time.<ref>{{Cite web |title=Virginia Information |url=http://www.bugbookcomputermuseum.com/BugBook-Titles-Originial.html |access-date=2023-03-06 |website=www.bugbookcomputermuseum.com}}</ref>

Early SBCs figured heavily in the early history of [[home computer]]s, such as the [[Acorn Electron]] and the [[BBC Micro]], also developed by Acorn. Other typical early single-board computers like the [[KIM-1]] were often shipped without [[Enclosure (electrical)|enclosure]], which had to be added by the owner. Other early examples are the [[Ferguson Big Board]], the [[Ampro|Ampro Little Board]],<ref>{{cite web|url=https://www.retrotechnology.com/restore/ampro_lb.html|title=Ampro Little Board|access-date=2020-09-05|archive-date=2020-02-07|archive-url=https://web.archive.org/web/20200207021815/http://www.retrotechnology.com/restore/ampro_lb.html|url-status=live}}</ref> and the [[Nascom]]. Many home computers in the 1980s were single-board computers, with some even encouraging owners to solder upgraded components directly to pre-marked points on the board.

As the PC became more prevalent, SBCs decreased in market share due to their low extensibility. The rapid adoption of [[IBM PC compatible|IBM's standards for peripherals]] and the standardization of the [[Peripheral Component Interconnect|PCI]] bus in the 1990s made motherboards and compatible components and peripherals cheap and ubiquitous, while the development of multimedia platforms such as the [[CD-ROM]] and [[Sound Blaster]] cards had begun to fast outpace the rate at which users needed to replace their personal computers. These two trends disincentivized single-board computers, and instead encouraged the proliferation of [[motherboard]]s, which typically housed the [[Central processing unit|CPU]] and other core components, with peripheral components such as hard disk drive controllers and [[graphics processor]]s, and even some core components such as [[Random-access memory|RAM]] modules, located on [[daughterboard]]s.

Computers began to move back towards fewer boards in the 2000s. As new standards like [[USB]] dramatically reduced the variety of peripheral standards motherboards were expected to support, advances in [[integrated circuit]] manufacturing provided new chipsets which could provide the functionality of many daughterboards, particularly [[Input/output|I/O]], in a single chip. By the end of the decade, PC motherboards offered on-board support for disk drives including [[Integrated Drive Electronics|IDE]], [[SATA]], [[NVMe]], [[RAID]], integrated [[GPU]], [[Ethernet]], and traditional I/O such as [[serial port]] and [[parallel port]], [[USB]], and keyboard/mouse support. Plug-in "cards" retained their importance as high performance components, such as physically large and complex [[graphics card|graphics coprocessor]]s, high-end [[RAID controller]]s, and specialized I/O cards such as [[data acquisition]] and [[Digital signal processing|DSP]] boards.

The 2010s were defined by rapid and sustained growth in single-board computers, enabled largely by advances in integrated circuit production techniques that made it possible for the first time to include most or all of the core components of a motherboard on a [[System on a chip|single integrated circuit die]]. One of the more well known single-board-computers of the decade was the [[Raspberry Pi]], which was built around a custom [[Broadcom Inc.|Broadcom]] SoC with [[Open-source software|open-source]] drivers. Originally intended for education, the Raspberry Pi contained a number of features, such as optimized [[Linux]] support and programmable [[General-purpose input/output|GPIO]] pins, that were also greatly appealing to [[hobby]]ists, who used the Pi, and other comparable SBCs, for projects such as [[home automation]], [[Video game console emulator|video game emulation]], [[Media server|media streaming]], and other experimentation.<ref>{{Cite web |last=Cawley |first=Christian |date=2019-12-10 |title=19 Awesome Uses for a Raspberry Pi |url=https://www.makeuseof.com/tag/different-uses-raspberry-pi/ |access-date=2023-03-06 |website=MUO |language=en}}</ref> In industry, the rapid growth of [[smartphone]]s and other small-scale devices encouraged hardware manufacturers to move towards more frequent use of SoCs and the reduction of motherboards in size, extensibility and complexity, while the proliferation of the [[Internet of things|Internet of Things]] increased demand for small, cheap components that would allow unconventional devices to access the Internet. Both of these factors dramatically increased production of single-board computers throughout the decade.
 	
By the end of the 2010s and the early 2020s, many devices, including smartphones, [[tablet computer]]s, [[laptop]]s and other smart devices, are powered by single-board computers which utilize advanced SoCs ([[System on a Chip]]). While this has greatly increased performance and power efficiency, it has raised concerns that single-board computers, particularly those built around SoCs, are harder to repair and may be less friendly to attempts to monitor or modify instructions programmed into the boards by manufacturers.<ref>{{Cite web |date=2021-07-15 |title=What You Should Know About Right to Repair |url=https://www.nytimes.com/wirecutter/blog/what-is-right-to-repair/ |access-date=2023-03-06 |website=Wirecutter: Reviews for the Real World |language=en-US}}</ref>

==Applications==
[[Image:Densitron SBC all.JPG|thumb|A [[socket 3]] based 486 SBC with power supply and flatscreen]]

Single-board computers were made possible by increasing the density of [[integrated circuit]]s. A single-board configuration reduces a system's overall cost, by reducing the number of circuit boards required, and by eliminating connectors and bus driver circuits that would otherwise be used. By putting all the functions on one board, a smaller overall system can be obtained, for example, as in notebook computers. Connectors are a frequent source of reliability problems, so a single-board system eliminates these problems.<ref>Winn Rosch, ''Hardware Bible Fifth Edition'', Que, 1999 {{ISBN|0-7897-1743-3}} pp. 50-51</ref>

Single-board computers are now commonly defined across two distinct architectures: no slots and slot support.

[[Embedded system|Embedded]] SBCs are units providing all the required I/O with no provision for plug-in cards. Applications are typically [[gambling|gaming]] (slot machines, video poker), kiosk, and machine control [[automation]]. Embedded SBCs are much smaller than the [[ATX|ATX-type motherboard]] found in PCs, and provide an I/O mix more targeted to an industrial application, such as on-board digital and analog I/O, on-board bootable [[flash memory]] (eliminating the need for a [[disk drive]]), no video, etc.

The term ''single-board computer'' now generally applies to an architecture where the single-board computer is plugged into a [[backplane]] to provide for I/O cards. In the case of [[PC104]], the bus is not a backplane in the traditional sense but is a series of pin connectors allowing I/O boards to be stacked.

Single-board computers are most commonly used in industrial situations where they are used in [[rackmount]] format for process control or [[Embedded system|embedded]] within other devices to provide control and interfacing. They are used in deep-sea exploration on the ALICE deep sea probes and in outer space, on the [[Ariane (rocket family)|Ariane]] and [[Pegasus (rocket)|Pegasus]] rockets and [[Space Shuttle]].<ref>{{cite web|url=http://www.newmicros.com/|title=Single Board Computer Peripherals|publisher=Newmicros|access-date=July 7, 2017|archive-date=June 28, 2017|archive-url=https://web.archive.org/web/20170628190316/http://www.newmicros.com/|url-status=usurped}}</ref> Because of the very high levels of integration, reduced component counts and reduced connector counts, SBCs are often smaller, lighter, more power efficient and more reliable than comparable multi-board computers.<ref name="magicstrap-comp-multiboard-components">{{cite web|title=A UHF RFID Printed Circuit Board Solution|url=http://www.rfidconnect.com/MediaService.ashx?type=attachment&id=903a28c9-5831-414c-9181-e6e29be1df96|publisher=Magicstrap|access-date=26 November 2016|page=4|date=January 2012|archive-date=26 November 2016|archive-url=https://web.archive.org/web/20161126131549/http://www.rfidconnect.com/MediaService.ashx?type=attachment&id=903a28c9-5831-414c-9181-e6e29be1df96|url-status=live}}</ref>

The primary advantage of an ATX motherboard as compared to an SBC is cost. Motherboards are manufactured by the millions for the consumer and office markets allowing tremendous [[economies of scale]]. Single-board computers are a market niche and are manufactured less often and at a higher cost. Motherboards and SBCs now offer similar levels of feature integration meaning that a motherboard failure in either standard will require equivalent replacement.

==Types, standards==
Ranges of single-board computers include [[Raspberry Pi]], [[BeagleBoard]], [[Nano Pi]], [[Orange Pi]] and [[Banana Pi]].<ref>{{Cite web |last=updated |first=Brian Westover last |date=2021-05-27 |title=Raspberry Pi 4 Model B review |url=https://www.tomsguide.com/reviews/raspberry-pi-4-model-b |access-date=2023-04-29 |website=Tom's Guide |language=en}}</ref><ref>{{Cite web |last=Manager |first=Content |date=2023-01-29 |title=BeagleBone Black Review |url=https://electronicshacks.com/beaglebone-black-review/ |access-date=2023-04-29 |website=ElectronicsHacks |language=en-us}}</ref><ref>{{Cite web |last=Alderson |first=Alex |title=FriendlyELEC introduces new NanoPi R6C single-board computer for US$89 |url=https://www.notebookcheck.net/FriendlyELEC-introduces-new-NanoPi-R6C-single-board-computer-for-US-89.701310.0.html |access-date=2023-04-29 |website=Notebookcheck |language=en}}</ref><ref>{{Cite web |title=Introducing the Banana Pi BPI-M5 Pro with RK3576 SoC |url=https://boardor.com/blog/introducing-the-banana-pi-bpi-m5-pro-with-rk3576-soc |access-date=2025-01-18 |website=Boardor |language=en}}</ref>

One common variety of single-board computer uses standardized [[computer form factor]]s intended for use in a [[backplane]] enclosure. Some of these types are [[CompactPCI]], [[PXI]], [[VMEbus]], [[VXI]], and [[PICMG]]. SBCs have been built around various internal processing structures including the [[Intel]] architecture, [[multiprocessing]] architectures, and lower power processing systems like [[RISC]] and [[SPARC]]. In the Intel PC world, the intelligence and interface/control circuitry is placed on a plug-in board that is then inserted into a passive (or active) backplane. The result is similar to having a system built with a [[motherboard]], except that the backplane determines the slot configuration. Backplanes are available with a mix of slots ([[Industry Standard Architecture|ISA]], PCI, [[PCI-X]], [[PCI-Express]], etc.), usually totaling 20 or fewer, meaning it will fit in a 19" rackmount enclosure (17" wide chassis).

<!--Need an image of a PC104 board here-->
Some single-board computers have connectors that allow a stack of circuit boards, each containing expansion hardware, to be assembled without a traditional backplane. Examples of stacking SBC form factors include [[PC/104]], PC/104-''Plus'', [[PCI-104]], [[EPIC (form factor)|EPIC]], and EBX; these systems are commonly available for use in embedded control systems.

Stack-type SBCs often have memory provided on plug-cards such as [[SIMM]]s and [[DIMM]]s. [[Hard drive]] circuit boards are also not counted for determining if a computer is an SBC or not for two reasons, firstly because the HDD is regarded as a single block storage unit, and secondly because the SBC may not require a hard drive at all as most can be booted from their network connections.

==Form factors==
*[[Advanced Telecommunications Computing Architecture|AdvancedTCA]]
*[[CompactPCI]]
*[[Embedded Compact Extended]] (ECX)
*[[Mini-ITX]]
*[[Multibus]]
*[[PC/104]]
*[[PICMG]]
*[[Pico-ITX]]
*[[PXI]]
*[[Qseven]]
*[[VMEbus]]
*[[VPX]]
*[[VXI]]
*[[96Boards]] (CE, EE, EETV and IE)

==See also==
*[[Computer on module]]
*[[Embedded system]]
*[[Motherboard]]
*[[Plug computer]]
*[[Single-board microcontroller]]
*[[System on a chip]]
*[[List of open-source computing hardware]]
*[[Raspberry Pi]]
*[[Nano Pi]]
*[[Orange Pi]]
*[[Banana Pi]]

==References==
{{commons category|Single-board computers}}
{{reflist}}

{{Single-board computer}}
{{Computer sizes}}
{{Embedded systems}}
{{Authority control}}

[[Category:Microcomputers]]
[[Category:Single-board computers| ]]