Computer hardware: Difference between revisions

Latest revision as of 05:21, 15 May 2026

Short description: Physical components of a computer

Computer hardware includes the physical parts of a computer, such as the central processing unit (CPU), random-access memory (RAM), motherboard, computer data storage, graphics card, sound card, and computer case. It includes external devices such as a monitor, mouse, keyboard, and speakers.^[1]^[2]

By contrast, software is a set of written instructions that can be stored and run by hardware. Hardware derived its name from the fact that it is hard or rigid with respect to changes, whereas software is soft because it is easy to change.

Hardware is typically directed by the software to execute any command or instruction. A combination of hardware and software forms a usable computing system, although other systems exist with only hardware.

History

Some of the earliest computing devices date back to the seventeenth century. For example, in 1642, French mathematician Blaise Pascal designed a gear-based device called the Pascaline that could add and subtract. Then, in 1676, the stepped reckoner was invented by Gottfried Leibniz, which could also divide and multiply. Due to the limitations of contemporary fabrication and design flaws, Leibniz' reckoner was not very functional, but similar devices (Leibniz wheel) remained in use into the 1970s.^[3] In the 19th century, Englishman Charles Babbage invented the difference engine, a mechanical device to calculate polynomials for astronomical purposes.^[4] Babbage also designed a general-purpose computer that was never built. Much of the design was incorporated into the earliest computers: punch cards for input and output, memory, an arithmetic unit analogous to central processing units, and even a primitive programming language similar to assembly language.^[5]

In 1936, Alan Turing developed the concept of the universal Turing machine to model any type of computer, demonstrating that no machine could solve the decision problem. ^[6] The universal Turing machine was a type of stored-program computer capable of mimicking the operations of any Turing machine (computer model) based on the software instructions passed to it. The storage of computer programs is key to the operation of modern computers and is the connection between computer hardware and software.^[7] Even prior to this, in the mid-19th century mathematician George Boole invented Boolean algebra—a system of logic where each proposition is either true or false. Boolean algebra is now the basis of the circuits that model the transistors and other components of integrated circuits that make up modern computer hardware.^[8] In 1945, Turing finished the design for a computer (the Automatic Computing Engine) that was never built.^[9]

Around this time, technological advancement in relays and vacuum tubes enabled the construction of the first computers.^[10] Building on Babbage's design, relay computers were built by George Stibitz at Bell Laboratories and Harvard University's Howard Aiken, who engineered the MARK I.^[5] Also in 1945, mathematician John von Neumann—working on the ENIAC project at the University of Pennsylvania—devised the underlying von Neumann architecture that has served as the template for most modern computers.^[11] Von Neumann's design featured a centralized memory that stored both data and programs, a central processing unit (CPU) with priority of access to the memory, and input and output (I/O) units. Von Neumann used a single bus to transfer data, meaning that his solution to the storage problem by locating programs and data adjacent to each other created the Von Neumann bottleneck when the system tries to fetch both at the same time—often throttling the system's performance.^[12]

Computer architecture

Computer architecture involves balancing various goals, such as cost, speed, availability, and energy efficiency. Designers must have a thorough understanding of hardware requirements and diverse aspects of computing, ranging from compilers to Integrated circuit design. ^[14] Cost has also become a significant constraint for manufacturers seeking to sell their products for less money than competitors offering a very similar hardware component. Profit margins have also been reduced.^[15] Even when the performance is not increasing, the cost of components has been dropping over time due to improved manufacturing techniques that have fewer components rejected at quality assurance stage.^[16]

Instruction set architecture

The most common instruction set architecture (ISA)—the interface between a computer's hardware and software—is based on the one devised by von Neumann in 1945.^[17] Despite the separation of the computing unit and the I/O system in many diagrams, typically the hardware is shared, with a bit in the computing unit indicating whether it is in computation or I/O mode.^[18] Common types of ISAs include CISC (complex instruction set computer), RISC (reduced instruction set computer), vector operations, and hybrid modes.^[19] CISC involves using a larger expression set to minimize the number of instructions the machines need to use.^[20] Based on a recognition that only a few instructions are commonly used, RISC shrinks the instruction set for added simplicity, which also enables the inclusion of more registers.^[21] After the invention of RISC in the 1980s, RISC based architectures that used pipelining and caching to increase performance displaced CISC architectures, particularly in applications with restrictions on power usage or space (such as mobile phones). From 1986 to 2003, the annual rate of improvement in hardware performance exceeded 50 percent, enabling the development of new computing devices such as tablets and mobiles.^[22] Alongside the density of transistors, DRAM memory as well as flash and magnetic disk storage also became exponentially more compact and cheaper. The rate of improvement slackened off in the twenty-first century.^[23]

In the twenty-first century, increases in performance have been driven by increasing exploitation of parallelism.^[24] Applications are often parallelizable in two ways: either the same function is running across multiple areas of data (data parallelism) or different tasks can be performed simultaneously with limited interaction (task parallelism).^[25] These forms of parallelism are accommodated by various hardware strategies, including instruction-level parallelism (such as instruction pipelining), vector architectures and graphical processing units (GPUs) that are able to implement data parallelism, thread-level parallelism and request-level parallelism (both implementing task-level parallelism).^[25]

Microarchitecture

Microarchitecture, also known as computer organization, refers to high-level hardware questions such as the design of the CPU, memory, and memory interconnect.^[26] Memory hierarchy ensures that the memory quicker to access (and more expensive) is located closer to the CPU, while slower, cheaper memory for large-volume storage is located further away.^[27] Memory is typically segregated to separate programs from data and limit an attacker's ability to alter programs.^[28] Most computers use virtual memory to simplify addressing for programs, using the operating system to map virtual memory to different areas of the finite physical memory.^[29]

Cooling

Computer processors generate heat, and excessive heat impacts their performance and can harm the components. Many computer chips will automatically throttle their performance to avoid overheating. Computers also typically have mechanisms for dissipating excessive heat, such as air or liquid coolers for the CPU and GPU and heatsinks for other components, such as the RAM. Computer cases are also often ventilated to help dissipate heat from the computer.^[30] Data centers typically use more sophisticated cooling solutions to keep the operating temperature of the entire center safe. Air-cooled systems are more common in smaller or older data centers, while liquid-cooled immersion (where each computer is surrounded by cooling fluid) and direct-to-chip (where the cooling fluid is directed to each computer chip) can be more expensive but are also more efficient.^[31] Most computers are designed to be more powerful than their cooling system, but their sustained operations cannot exceed the capacity of the cooling system.^[32] While performance can be temporarily increased when the computer is not hot (overclocking),^[33] in order to protect the hardware from excessive heat, the system will automatically reduce performance or shut down the processor if necessary.^[32] Processors will also shut off or enter a low power mode when inactive to reduce heat.^[34] Power delivery as well as heat dissipation are the most challenging aspects of hardware design,^[35] and have been the limiting factor to the development of smaller and faster chips since the early twenty-first century.^[34] Increases in performance require a commensurate increase in energy use and cooling demand.^[36]

Types of computer hardware systems

Personal computer

The personal computer is one of the most common types of computers due to its versatility and relatively low price.

Desktop personal computers have a monitor, a keyboard, a mouse, and a computer case. The computer case holds the motherboard, fixed or removable disk drives for data storage, the power supply, and may contain other peripheral devices such as modems or network interfaces. Some models of desktop computers integrated the monitor and keyboard into the same case as the processor and power supply. Separating the elements allows the user to arrange the components in a pleasing, comfortable array, at the cost of managing power and data cables between them.
Laptops are designed for portability but operate similarly to desktop PCs.^[37] They may use lower-power or reduced size components, with lower performance than a similarly priced desktop computer.^[38] Laptops contain the keyboard, display, and processor in one case. The monitor in the folding upper cover of the case can be closed for transportation to protect the screen and keyboard. Instead of a mouse, laptops may have a touchpad or pointing stick.
Tablets are portable computers that use a touch screen as the primary input device. Tablets generally weigh less and are smaller than laptops.^{[citation needed]} Some tablets include fold-out keyboards or offer connections to separate external keyboards. Some models of laptop computers have a detachable keyboard, which allows the system to be configured as a touch-screen tablet. They are sometimes called 2-in-1 detachable laptops or tablet-laptop hybrids.^[39]
Mobile phones are designed to have an extended battery life and light weight, while having less functionality than larger computers. They have diverse hardware architecture, often including antennas, microphones, cameras, GPS devices, and speakers. Power and data connections vary between phones.^[40]

Large-scale computers

A mainframe computer is a much larger computer that typically fills a room and may cost many hundreds or thousands of times as much as a personal computer. They are designed to perform large numbers of calculations for governments and large enterprises.
In the 1960s and 1970s, more and more departments started to use cheaper and dedicated systems for specific purposes like process control and laboratory automation. A minicomputer, or colloquially mini, is a class of smaller computers that was developed in the mid-1960s^[41]^[42] and sold for much less than mainframe^[43] and mid-size computers from IBM and its direct competitors.
Supercomputers can cost hundreds of millions of dollars. They are designed to maximize performance in floating-point arithmetic and execute batch programs that may take weeks to complete. Due to the need for efficient communication between parallel programs, the speed of the internal network is a critical priority.^[44]
Warehouse scale computers are larger versions of cluster computers that came into fashion with software as a service provided via the internet. Their design is intended to minimize cost per operation and power usage, as they can cost over $100 million for a warehouse and the computers that go inside (the computers must be replaced every few years). Although availability is crucial for SaaS products, the software is designed to compensate for availability failures—unlike supercomputers.^[44]

Virtual hardware

Virtual hardware is software that mimics the function of hardware; it is commonly used in infrastructure as a Service (IaaS) and platform as a Service (PaaS).^[45]

Embedded system

Embedded systems have the most variation in their processing power and cost: from an 8-bit processor that could cost less than USD$0.10, to higher-end processors capable of billions of operations per second and costing over USD$100. Cost is a particular concern with these systems, with designers often choosing the cheapest option that satisfies the performance requirements.^[46]

Components

Case

A computer case encloses most of the components of a desktop computer system. It provides mechanical support and protection for internal elements such as the motherboard, disk drives, and power supply, and controls and directs the flow of cooling air over internal components. The case is also part of the system to control electromagnetic interference radiated by the computer and protects internal parts from electrostatic discharge. Large tower cases provide space for multiple disk drives or other peripherals and usually stand on the floor, while desktop cases provide less expansion room. All-in-one style designs include a video display built into the same case. Portable and laptop computers require cases that provide impact protection for the unit. Hobbyists may decorate the cases with colored lights, paint, or other features, in an activity called case modding.

Power supply

Most personal computer power supply units meet the ATX standard and convert from alternating current (AC) at between 120 and 277 volts provided from a power outlet to direct current (DC) at a much lower voltage: typically 12, 5, or 3.3 volts.^[47]

Motherboard

The motherboard is the main component of a computer. It is a board with integrated circuitry that connects the other parts of the computer including the CPU, the RAM, the disk drives (CD, DVD, hard disk, or any others) as well as any peripherals connected via the ports or the expansion slots. The integrated circuit (IC) chips in a computer typically contain billions of tiny metal–oxide–semiconductor field-effect transistors (MOSFETs).^[48]

Components directly attached to or to part of the motherboard include:

At least one CPU (central processing unit), which performs the majority of computational tasks required for a computer to operate.^[49] Often described informally as the brain of the computer,^[50] the CPU fetches program instructions from random-access memory (RAM), decodes and executes them, then returns results for further processing by other components. This process is known as the instruction cycle. Modern CPUs are microprocessors fabricated on a metal–oxide–semiconductor (MOS) integrated circuit (IC) using advanced semiconductor device fabrication techniques, often employing photolithography. They are typically cooled using a heatsink and fan or a liquid-cooling system. Many contemporary CPUs integrate an on-die graphics processing unit (GPU), eliminating the need for a discrete GPU in basic systems. CPU performance is influenced by clock speed—measured in gigahertz (GHz)—with common consumer processors ranging from 1 GHz to 5 GHz.^{[citation needed]} Additionally, there is a growing trend toward multi-core designs, where multiple processing cores are included on a single chip, enabling greater parallelism and improved multitasking performance.^[50]
The internal bus connects the CPU to main memory via multiple communication lines—typically 50 to 100—divided into address, data, and control buses, each handling specific types of signals.^[51] Historically, parallel buses were dominant, but in the twenty-first century, high-speed serial buses (often using serializer/deserializer (SerDes) technology) have largely replaced them, enabling greater data throughput over fewer physical connections. Examples include PCI Express and USB.^[52] In systems with multiple processors, an interconnect bus is used, traditionally coordinated by a northbridge chip, which links the CPU, memory, and high-speed peripherals such as PCI. The southbridge handles communication with slower I/O devices such as storage and USB ports.^[53] However, in modern architectures like Intel QuickPath Interconnect or AMD Ryzen-based systems, these functions are increasingly integrated into the CPU itself, forming a system on a chip (SoC)-like design.
Random-access memory (RAM) stores code and data actively used by the CPU, organized in a memory hierarchy optimized for access speed and predicted reuse. At the top of this hierarchy are registers, located within the CPU core, offering the fastest access but extremely limited capacity.^[54] Below registers are multiple levels of cache memory—L1, L2, and sometimes L3—typically implemented using static random-access memory (SRAM). Caches have greater capacity than registers but less than main memory, and while slower than registers, they are significantly faster than dynamic random-access memory (DRAM), which is used for main RAM.^[55] Caching improves performance by prefetching frequently used data, thereby reducing memory latency.^[55]^[56] When data is not found in the cache (a cache miss), it is retrieved from main memory. RAM is volatile, meaning its contents are lost when the system loses power.^[57] In modern systems, DRAM is often of the DDR SDRAM type, such as DDR4 or DDR5.
Permanent storage or non-volatile memory is typically higher capacity and cheaper than memory, but takes much longer to access. Historically, such storage was typically provided in the form of a hard drive, but solid-state drives (SSD) are becoming cheaper and are much faster, thus leading to their increasing adoption. USB drives and network or cloud storage are also options.^[58]
Read-only memory (ROM) contains firmware such as the BIOS (Basic Input/Output System), which initializes hardware during the boot process—known as booting or bootstrapping—when the computer is powered on.^{[citation needed]} This firmware is stored in a non-volatile memory chip, traditionally ROM or flash memory, allowing updates in modern systems via firmware update.^[59]
- The BIOS manages essential functions, including boot sequence and power management through the ACPI standard. However, most modern motherboards have transitioned to the Unified Extensible Firmware Interface (UEFI), which offers enhanced capabilities, faster startup times, support for GUID Partition Table (GPT), and secure boot features.
The CMOS (complementary MOS) battery, which powers the CMOS memory for date and time in the BIOS chip. This battery is generally a watch battery.
Power MOSFETs make up the voltage regulator module (VRM), which controls how much voltage other hardware components receive.^[60]

Expansion cards

An expansion card in computing is a printed circuit board that can be inserted into an expansion slot of a computer motherboard or backplane to add functionality to a computer system via the expansion bus. Expansion cards can be used to obtain or expand on features not offered by the motherboard.^[61] Using expansion cards for a video processor used to be common, but modern computers are more likely to instead have a GPU integrated into the motherboard.^[62]

Input/output

Most computers also have an external data bus to connect peripheral devices to the motherboard. Most commonly, Universal Serial Bus (USB) is used.^[63] Unlike the internal bus, the external bus is connected using a bus controller that allows the peripheral system to operate at a different speed from the CPU.^[63] Input and output devices are used to receive data from the external world or write data, respectively. Common examples include keyboards and mice (input) and displays and printers (output). Network interface controllers are used to access the Internet.^[64] USB ports also allow power to connected devices—a standard USB supplies power at 5 volts and up to 500 milliamps (2.5 watts), while powered USB ports with additional pins may allow the delivery of more power—up to 6 amps at 24v.^[65]

Sales

Global revenue from computer hardware in 2023 reached $705.17 billion.^[66]

Recycling

Because computer parts contain hazardous materials, there is a growing movement to recycle old and outdated devices.^[67] Computer hardware contains hazardous substances such as lead, mercury, nickel, and cadmium. According to the EPA, these e-wastes negatively affect the environment if not disposed of properly. Hardware manufacturing also requires significant energy, while recycling components helps reduce air and water pollution as well as greenhouse gas emissions.^[68] In many regions, improper disposal of computer equipment is illegal, and legislation requires recycling through government-approved facilities. Recycling can be facilitated by removing reusable parts such as RAM, DVD drives, graphics cards, hard drives, SSDs, and other similar components.

Many materials used in computer hardware can be recovered through recycling for use in future production. The reuse of tin, silicon, iron, aluminum, and various plastics commonly found in computers and other electronics helps reduce the costs of manufacturing new systems. Hardware components also frequently contain copper, gold, tantalum,^[69]^[70] silver, platinum, palladium, and lead, along with other valuable materials suitable for reclamation.^[71]^[72]

Toxic computer components

The central processing unit contains several toxic materials. It may include lead and chromium in metal plates. Resistors, semiconductors, infrared detectors, stabilizers, cables, and wires can contain cadmium, while computer circuit boards may also contain mercury and chromium.^[73] Improper disposal of these materials and chemicals can pose serious hazards to the environment.

Environmental effects

When e-waste byproducts leach into groundwater, are burned, or get mishandled during recycling, it causes harm. Health problems associated with such toxins include impaired mental development, cancer, and damage to the lungs, liver, and kidneys.^[74] Computer components contain many toxic substances, like dioxins, polychlorinated biphenyls (PCBs), cadmium, chromium, radioactive isotopes and mercury. Circuit boards contain considerable quantities of lead-tin solders that are more likely to leach into groundwater or create air pollution due to incineration.^[75]

Recycling of computer hardware is considered environmentally friendly because it prevents hazardous waste, including heavy metals and carcinogens, from entering the atmosphere, landfill or waterways. While electronics consist a small fraction of total waste generated, they are far more dangerous. There is stringent legislation designed to enforce and encourage the sustainable disposal of appliances, the most notable being the Waste Electrical and Electronic Equipment Directive of the European Union and the United States National Computer Recycling Act.^[76]

Efforts for minimizing computer hardware waste

E-cycling, the recycling of computer hardware, refers to the donation, reuse, shredding and general collection of used electronics. Generically, the term refers to the process of collecting, brokering, disassembling, repairing and recycling the components or metals contained in used or discarded electronic equipment, otherwise known as electronic waste (e-waste). E-cyclable items include, but are not limited to: televisions, computers, microwave ovens, vacuum cleaners, telephones and cellular phones, stereos, and VCRs and DVDs just about anything that has a cord, light or takes some kind of battery.^[77]

Some companies, such as Dell and Apple, will recycle computers of their own make or any other make. Otherwise, a computer can be donated to Computer Aid International which is an organization that recycles and refurbishes old computers for hospitals, schools, universities, etc.^[78]

References

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Sources

Blum, Edward K. (2011) (in en). Computer Science: The Hardware, Software and Heart of It. Springer Science & Business Media. ISBN 978-1-4614-1168-0.
Hennessy, John L.; Patterson, David A. (2011) (in en). Computer Architecture: A Quantitative Approach. Elsevier. ISBN 978-0-12-383872-8.
Mendelson, Avi (2022). "The Architecture". in Anupam Chattopadhyay (in en). Handbook of Computer Architecture. Springer Nature. pp. 1–42. doi:10.1007/978-981-15-6401-7_1-1. ISBN 978-981-15-6401-7. https://link.springer.com/referenceworkentry/10.1007/978-981-15-6401-7_1-1.
Wang, Shuangbao Paul (2021) (in en). Computer Architecture and Organization: Fundamentals and Architecture Security. Springer Nature. ISBN 978-981-16-5662-0.

External links

Computer hardware at Wikibooks

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[1] "Parts of computer". Microsoft. http://windows.microsoft.com/en-us/windows-vista/parts-of-a-computer.

[2] Gilster, Ron (2001). PC hardware : a beginner's guide. Internet Archive. New York; London : McGraw-Hill. ISBN 978-0-07-212990-8. http://archive.org/details/pchardwarebeginn00gils.

[FOOTNOTEBlum201113–14-3] Blum 2011, p. 13–14.

[FOOTNOTEBlum201114-4] Blum 2011, p. 14.

[FOOTNOTEBlum201115-5] 5.0 ^5.1 Blum 2011, p. 15.

[FOOTNOTEBlum201121,_23-6] Blum 2011, pp. 21, 23.

[FOOTNOTEBlum201125-7] Blum 2011, p. 25.

[FOOTNOTEBlum201134–35-8] Blum 2011, pp. 34–35.

[FOOTNOTEBlum201171–72-9] Blum 2011, pp. 71–72.

[FOOTNOTEBlum201172-10] Blum 2011, p. 72.

[FOOTNOTEBlum201172,_74-11] Blum 2011, pp. 72, 74.

[FOOTNOTEBlum201174-12] Blum 2011, p. 74.

[FOOTNOTEHennessyPatterson201141–42-13] Hennessy & Patterson 2011, pp. 41–42.

[FOOTNOTEHennessyPatterson201111-14] Hennessy & Patterson 2011, p. 11.

[FOOTNOTEHennessyPatterson201127–28,_32-15] Hennessy & Patterson 2011, pp. 27–28, 32.

[FOOTNOTEHennessyPatterson201127-16] Hennessy & Patterson 2011, p. 27.

[FOOTNOTEMendelson20222-17] Mendelson 2022, p. 2.

[FOOTNOTEMendelson20222–3-18] Mendelson 2022, pp. 2–3.

[FOOTNOTEMendelson20223-19] Mendelson 2022, p. 3.

[FOOTNOTEMendelson20228-20] Mendelson 2022, p. 8.

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@@ Line 1: / Line 1: @@
 {{short description|Physical components of a computer}}
-[[File:PDP-11-M7270.jpg|thumb|upright|[[Engineering:PDP-11|PDP-11]] CPU board]]
+[[File:PDP-11-M7270.jpg|thumb|upright|[[PDP-11]] CPU board]]
-'''Computer hardware''' includes the physical parts of a [[Computer|computer]], such as the [[Engineering:Computer case|case]], [[Central processing unit|central processing unit]] (CPU), [[Random-access memory|random access memory (RAM)]], [[Engineering:Computer monitor|monitor]], [[Computer mouse|mouse]], [[Computer keyboard|keyboard]], [[Computer data storage|computer data storage]], [[Engineering:Graphics card|graphics card]], [[Engineering:Sound card|sound card]], [[Engineering:Computer speakers|speakers]] and [[Engineering:Motherboard|motherboard]].<ref>{{cite web |title=Parts of computer |url=http://windows.microsoft.com/en-us/windows-vista/parts-of-a-computer |publisher=Microsoft |access-date=5 December 2013 |url-status=live |archive-url=https://web.archive.org/web/20131127145607/http://windows.microsoft.com/en-US/windows-vista/Parts-of-a-computer |archive-date=27 November 2013 |df=dmy-all }}</ref><ref>{{Cite book |last=Gilster |first=Ron |url=http://archive.org/details/pchardwarebeginn00gils |title=PC hardware : a beginner's guide |date=2001 |publisher=New York; London : McGraw-Hill |others=Internet Archive |isbn=978-0-07-212990-8}}</ref>
+'''Computer hardware''' includes the physical parts of a [[Computer|computer]], such as the [[Central processing unit|central processing unit]] (CPU), [[Random-access memory|random-access memory]] (RAM), [[Engineering:Motherboard|motherboard]], [[Computer data storage|computer data storage]], [[Engineering:Graphics card|graphics card]], [[Engineering:Sound card|sound card]], and [[Engineering:Computer case|computer case]]. It includes external devices such as a [[Engineering:Computer monitor|monitor]], [[Computer mouse|mouse]], [[Computer keyboard|keyboard]], and [[Engineering:Computer speakers|speakers]].<ref>{{cite web |title=Parts of computer |url=http://windows.microsoft.com/en-us/windows-vista/parts-of-a-computer |publisher=Microsoft |access-date=5 December 2013 |url-status=live |archive-url=https://web.archive.org/web/20131127145607/http://windows.microsoft.com/en-US/windows-vista/Parts-of-a-computer |archive-date=27 November 2013 |df=dmy-all }}</ref><ref>{{Cite book |last=Gilster |first=Ron |url=http://archive.org/details/pchardwarebeginn00gils |title=PC hardware : a beginner's guide |date=2001 |publisher=New York; London : McGraw-Hill |others=Internet Archive |isbn=978-0-07-212990-8}}</ref>
-By contrast, [[Software|software]] is the set of instructions that can be stored and run by hardware. Hardware is so-termed because it is ''[[Physics:Hardness|hard]]'' or rigid with respect to changes, whereas software is ''soft'' because it is easy to change.
+By contrast, [[Software|software]] is a set of written instructions that can be stored and run by hardware. Hardware derived its name from the fact that it is ''[[Physics:Hardness|hard]]'' or rigid with respect to changes, whereas software is ''soft'' because it is easy to change.
 Hardware is typically directed by the software to execute any command or instruction. A combination of hardware and software forms a usable [[Computing|computing]] system, although [[Engineering:Digital electronics|other systems]] exist with only hardware.
-==Von Neumann architecture==
+==History==
-{{Main|Von Neumann architecture|Stored-program computer}}
+Some of the earliest computing devices date back to the seventeenth century. For example, in 1642, French mathematician [[Biography:Blaise Pascal|Blaise Pascal]] designed a gear-based device called the [[Engineering:Pascaline|Pascaline]] that could add and subtract. Then, in 1676, the [[Stepped reckoner|stepped reckoner]] was invented by Gottfried Leibniz, which could also divide and multiply. Due to the limitations of contemporary fabrication and design flaws, Leibniz' reckoner was not very functional, but similar devices ([[Leibniz wheel]]) remained in use into the 1970s.{{sfn|Blum|2011|p=13–14}} In the 19th century, Englishman Charles Babbage invented the [[Difference engine|difference engine]], a mechanical device to calculate [[Polynomial|polynomial]]s for astronomical purposes.{{sfn|Blum|2011|p=14}} Babbage also designed a general-purpose computer that was never built. Much of the design was incorporated into the earliest computers: punch cards for input and output, memory, an arithmetic unit analogous to [[Central processing unit|central processing unit]]s, and even a primitive [[Programming language|programming language]] similar to [[Assembly language|assembly language]].{{sfn|Blum|2011|p=15}}
+In 1936, [[Biography:Alan Turing|Alan Turing]] developed the concept of the [[Universal Turing machine|universal Turing machine]] to model any type of computer, demonstrating that no machine could solve the [[Entscheidungsproblem|decision problem]].
+{{sfn|Blum|2011|pp=21, 23}} The universal Turing machine was a type of [[Stored-program computer|stored-program computer]] capable of mimicking the operations of any [[Turing machine]] (computer model) based on the [[Software|software]] instructions passed to it. The storage of [[Computer program|computer program]]s is key to the operation of modern computers and is the connection between computer hardware and software.{{sfn|Blum|2011|p=25}} Even prior to this, in the mid-19th century mathematician [[Biography:George Boole|George Boole]] invented [[Boolean algebra]]—a system of logic where each [[Proposition|proposition]] is either true or false. Boolean algebra is now the basis of the [[Circuit (computer science)|circuit]]s that model the [[Engineering:Transistor|transistor]]s and other components of [[Engineering:Integrated circuit|integrated circuit]]s that make up modern computer hardware.{{sfn|Blum|2011|pp=34-35}} In 1945, Turing finished the design for a computer (the Automatic Computing Engine) that was never built.{{sfn|Blum|2011|pp=71-72}}
 [[File:Von Neumann Architecture.svg|thumb|Von Neumann architecture scheme]]
+Around this time, technological advancement in [[Engineering:Relay|relay]]s and [[Physics:Vacuum tube|vacuum tube]]s enabled the construction of the first computers.{{sfn|Blum|2011|p=72}}  Building on Babbage's design, relay computers were built by George Stibitz at Bell Laboratories and [[Organization:Harvard University|Harvard University]]'s Howard Aiken, who engineered the [[Engineering:Harvard Mark I|MARK I]].{{sfn|Blum|2011|p=15}} Also in 1945, mathematician [[Biography:John von Neumann|John von Neumann]]—working on the [[Engineering:ENIAC|ENIAC]] project at the [[Organization:University of Pennsylvania|University of Pennsylvania]]—devised the underlying [[Von Neumann architecture|von Neumann architecture]] that has served as the template for most modern computers.{{sfn|Blum|2011|pp=72, 74}} Von Neumann's design featured a centralized memory that stored both data and programs, a [[Central processing unit|central processing unit]] (CPU) with priority of access to the memory, and input and output (I/O) units. Von Neumann used a single [[Engineering:Bus (computing)|bus]] to transfer data, meaning that his solution to the storage problem by locating programs and data adjacent to each other created the Von Neumann bottleneck when the system tries to fetch both at the same time—often throttling the system's performance.{{sfn|Blum|2011|p=74}}
+==Computer architecture==
+<!-- [[File:Computer architecture block diagram.png|alt=|thumb|481x481px|Block diagram of a basic computer with uniprocessor CPU. Black lines indicate control flow, whereas red lines indicate data flow. Arrows indicate the direction of flow.]] -->
+[[File:Growth in processor performance, 1978–2010.png|thumb|Growth in processor performance (as measured by benchmarks),{{sfn|Hennessy |Patterson|2011|pp=41-42}} 1978–2010]]
+Computer architecture involves balancing various goals, such as cost, speed, availability, and energy efficiency. Designers must have a thorough understanding of hardware requirements and diverse aspects of computing, ranging from [[Compiler|compiler]]s to [[Engineering:Integrated circuit design|Integrated circuit design]]. {{sfn|Hennessy |Patterson|2011|p=11}} Cost has also become a significant constraint for manufacturers seeking to sell their products for less money than competitors offering a very similar hardware component. Profit margins have also been reduced.{{sfn|Hennessy |Patterson|2011|pp=27-28, 32}} Even when the performance is not increasing, the cost of components has been dropping over time due to improved manufacturing techniques that have fewer components rejected at [[Quality assurance|quality assurance]] stage.{{sfn|Hennessy |Patterson|2011|p=27}}
+===Instruction set architecture===
+The most common [[Instruction set architecture|instruction set architecture]] (ISA)—the interface between a computer's hardware and software—is based on the one devised by von Neumann in 1945.{{sfn|Mendelson|2022|p=2}} Despite the separation of the computing unit and the I/O system in many diagrams, typically the hardware is shared, with a bit in the computing unit indicating whether it is in computation or I/O mode.{{sfn|Mendelson|2022|pp=2-3}} Common types of ISAs include CISC ([[Complex instruction set computer|complex instruction set computer]]), RISC ([[Reduced instruction set computer|reduced instruction set computer]]), [[Vector processor|vector operations]], and hybrid modes.{{sfn|Mendelson|2022|p=3}} CISC involves using a larger expression set to minimize the number of instructions the machines need to use.{{sfn|Mendelson|2022|p=8}} Based on a recognition that only a few instructions are commonly used, RISC shrinks the instruction set for added simplicity, which also enables the inclusion of more registers.{{sfn|Mendelson|2022|p=15}} After the invention of RISC in the 1980s, RISC based architectures that used [[Pipeline (computing)|pipelining]] and caching to increase performance displaced CISC architectures, particularly in applications with restrictions on power usage or space (such as [[Engineering:Mobile phone|mobile phone]]s). From 1986 to 2003, the annual rate of improvement in hardware performance exceeded 50 percent, enabling the development of new computing devices such as [[Engineering:Tablet computer|tablet]]s and mobiles.{{sfn|Hennessy |Patterson|2011|p=2}} Alongside the density of transistors, DRAM memory as well as flash and magnetic disk storage also became exponentially more compact and cheaper. The rate of improvement slackened off in the twenty-first century.{{sfn|Hennessy |Patterson|2011|pp=17–18}}
+In the twenty-first century, increases in performance have been driven by increasing exploitation of [[Parallel computing|parallelism]].{{sfn|Hennessy |Patterson|2011|pp=9, 44}} Applications are often parallelizable in two ways: either the same function is running across multiple areas of data ([[Data parallelism|data parallelism]]) or different tasks can be performed simultaneously with limited interaction ([[Task parallelism|task parallelism]]).{{sfn|Hennessy |Patterson|2011|p=9}} These forms of parallelism are accommodated by various hardware strategies, including [[Instruction-level parallelism|instruction-level parallelism]] (such as [[Instruction pipelining|instruction pipelining]]), vector architectures and graphical processing units (GPUs) that are able to implement data parallelism, thread-level parallelism and request-level parallelism (both implementing task-level parallelism).{{sfn|Hennessy |Patterson|2011|p=9}}
+===Microarchitecture===
+[[Microarchitecture]], also known as computer organization, refers to high-level hardware questions such as the design of the CPU, memory, and memory [[Engineering:Interconnect (integrated circuits)|interconnect]].{{sfn|Hennessy |Patterson|2011|p=15}} [[Memory hierarchy]] ensures that the memory quicker to access (and more expensive) is located closer to the CPU, while slower, cheaper memory for large-volume storage is located further away.{{sfn|Wang|2021|p=3}} Memory is typically segregated to separate programs from data and limit an attacker's ability to alter programs.{{sfn|Wang|2021|p=4}} Most computers use [[Virtual memory|virtual memory]] to simplify addressing for programs, using the [[Operating system|operating system]] to map virtual memory to different areas of the finite physical memory.{{sfn|Wang|2021|pp=51-52}}
-The template for all modern computers is the [[Von Neumann architecture]], detailed in a 1945 paper by Hungarian mathematician [[Biography:John von Neumann|John von Neumann]]. This describes a design architecture for an electronic digital computer with subdivisions of a [[Central processing unit|processing unit]] consisting of an [[Arithmetic logic unit|arithmetic logic unit]] and [[Processor register|processor register]]s, a [[Control unit|control unit]] containing an [[Instruction register|instruction register]] and [[Program counter|program counter]], a [[Computer memory|memory]] to store both data and instructions, external [[Mass storage|mass storage]], and input and output mechanisms.<ref>{{Cite report|url=http://virtualtravelog.net.s115267.gridserver.com/wp/wp-content/media/2003-08-TheFirstDraft.pdf|title=First Draft of a Report on the EDVAC|last=von Neumann|first=John|date=June 30, 1945|publisher=[[Organization:University of Pennsylvania|University of Pennsylvania]]|id=Contract No. W-670-ORD-4926|access-date=6 December 2013|archive-url=https://web.archive.org/web/20130809184824/http://virtualtravelog.net.s115267.gridserver.com/wp/wp-content/media/2003-08-TheFirstDraft.pdf|archive-date=9 August 2013|url-status=dead|df=dmy-all}}</ref> The meaning of the term has evolved to mean a [[Stored-program computer|stored-program computer]] in which an instruction fetch and a data operation cannot occur at the same time because they share a common [[Engineering:Bus (computing)|bus]]. This is referred to as the Von Neumann bottleneck and often limits the performance of the system.<ref>{{cite web |last=Markgraf |first=Joey D. |title=The Von Neumann bottleneck |year=2007 |url=http://aws.linnbenton.edu/cs271c/markgrj/ |archive-url=https://web.archive.org/web/20110609220643/http://aws.linnbenton.edu/cs271c/markgrj/ |archive-date=9 June 2011 |access-date=24 August 2011}}</ref>
+===Cooling===
+Computer processors generate heat, and excessive heat impacts their performance and can harm the components. Many computer chips will automatically throttle their performance to avoid overheating. Computers also typically have mechanisms for dissipating excessive heat, such as air or liquid coolers for the CPU and GPU and heatsinks for other components, such as the RAM. [[Engineering:Computer case|Computer case]]s are also often ventilated to help dissipate heat from the computer.<ref>{{cite web  |title=PC Cooling: The Importance of Keeping Your PC Cool |url=https://www.intel.com/content/www/us/en/gaming/resources/pc-cooling-the-importance-of-keeping-your-pc-cool.html |website=Intel |access-date=20 July 2024 |language=en}}</ref> [[Data center]]s typically use more sophisticated cooling solutions to keep the operating temperature of the entire center safe. Air-cooled systems are more common in smaller or older data centers, while liquid-cooled immersion (where each computer is surrounded by cooling fluid) and direct-to-chip (where the cooling fluid is directed to each computer chip) can be more expensive but are also more efficient.<ref>{{cite web |title=Data Center Cooling: What are the top concepts you need to know? |url=https://gatewaymechanical.ca/data-center-cooling-what-you-need-to-know/ |website=gatewaymechanical.ca |access-date=20 July 2024 |language=en-CA |date=11 August 2021}}</ref> Most computers are designed to be more powerful than their cooling system, but their sustained operations cannot exceed the capacity of the cooling system.{{sfn|Hennessy |Patterson|2011|p=22}} While performance can be temporarily increased when the computer is not hot ([[Engineering:Overclocking|overclocking]]),{{sfn|Hennessy |Patterson|2011|p=26}} in order to protect the hardware from excessive heat, the system will automatically reduce performance or shut down the processor if necessary.{{sfn|Hennessy |Patterson|2011|p=22}} Processors will also shut off or enter a low power mode when inactive to reduce heat.{{sfn|Hennessy |Patterson|2011|p=25}} Power delivery as well as heat dissipation are the most challenging aspects of hardware design,{{sfn|Hennessy |Patterson|2011|p=21}} and have been the limiting factor to the development of smaller and faster chips since the early twenty-first century.{{sfn|Hennessy |Patterson|2011|p=25}} Increases in performance require a commensurate increase in energy use and cooling demand.{{sfn|Hennessy |Patterson|2011|p=56}}
-==Types of computer systems==
+==Types of computer hardware systems==
 ===Personal computer===
-[[File:Personal computer, exploded 6.svg|thumb|Basic hardware components of a  personal computer, including a monitor, a motherboard, a CPU, a [[Random-access memory|RAM]], two expansion cards, a power supply, an optical disc drive, a hard disk drive, a [[Computer keyboard|keyboard]] and a mouse]]
+[[File:Personal computer, exploded 6.svg|thumb|Basic hardware components of a  personal computer, including a [[Engineering:Computer monitor|monitor]], a [[Engineering:Motherboard|motherboard]], a CPU, a RAM, two [[Engineering:Expansion card|expansion card]]s, a power supply, an [[Engineering:Optical disc drive|optical disc drive]], a [[Engineering:Hard disk drive|hard disk drive]], a [[Computer keyboard|keyboard]] and a mouse]]
 [[File:Computer from inside 018.jpg|thumb|Inside a custom-built computer: power supply at the bottom has its own cooling fan]]
-The [[Engineering:Personal computer|personal computer]] is one of the most common types of computer due to its versatility and relatively low price. Desktop personal computers have  a [[Engineering:Computer monitor|monitor]], a [[Computer keyboard|keyboard]], a mouse, and a [[Engineering:Computer case|computer case]]. The computer case holds the [[Engineering:Motherboard|motherboard]], fixed or removable [[Engineering:Hard disk drive|disk drives]] for data storage, the power supply, and may contain other peripheral devices such as [[Modem|modem]]s or network interfaces.  Some models of desktop computers integrated the monitor and keyboard into the same case as the processor and power supply. Separating the elements allows the user to arrange the components in a pleasing, comfortable array, at the cost of managing power and data cables between them.
+The [[Engineering:Personal computer|personal computer]] is one of the most common types of computers due to its versatility and relatively low price.
-[[Engineering:Laptop|Laptop]]s are designed for portability but operate similarly to desktop PCs.<ref name="PC hardware">{{cite book |url=https://archive.org/details/pchardwarebeginn00gils/page/21 |title=PC hardware : a beginner's guide |date=26 April 2001 |publisher=Osborne/McGraw-Hill |isbn=9780072129908 |pages=[https://archive.org/details/pchardwarebeginn00gils/page/21 21]}}</ref> They may use lower-power or reduced size components, with lower performance than a similarly priced desktop computer.<ref name="desktop vs laptop computer">{{Cite web |url=https://www.computerhope.com/issues/ch001399.htm |title=Desktop computer vs. Laptop computer |date=2019-12-30 |website=www.computerhope.com |access-date=2020-01-15}}</ref> Laptops contain the keyboard, display, and processor in one case. The monitor in the folding upper cover of the case can be closed for transportation, to protect the screen and keyboard.  Instead of a mouse, laptops may have a [[Touchpad|touchpad]] or [[Engineering:Pointing stick|pointing stick]].
+*Desktop personal computers have  a [[Engineering:Computer monitor|monitor]], a [[Computer keyboard|keyboard]], a mouse, and a [[Engineering:Computer case|computer case]]. The computer case holds the [[Engineering:Motherboard|motherboard]], fixed or removable [[Engineering:Hard disk drive|disk drives]] for data storage, the power supply, and may contain other peripheral devices such as [[Modem|modem]]s or network interfaces.  Some models of desktop computers integrated the monitor and keyboard into the same case as the processor and power supply. Separating the elements allows the user to arrange the components in a pleasing, comfortable array, at the cost of managing power and data cables between them.
+*[[Engineering:Laptop|Laptop]]s are designed for portability but operate similarly to desktop PCs.<ref name="PC hardware">{{cite book |url=https://archive.org/details/pchardwarebeginn00gils/page/21 |title=PC hardware : a beginner's guide |date=26 April 2001 |publisher=Osborne/McGraw-Hill |isbn=9780072129908 |pages=[https://archive.org/details/pchardwarebeginn00gils/page/21 21]}}</ref> They may use lower-power or reduced size components, with lower performance than a similarly priced desktop computer.<ref name="desktop vs laptop computer">{{Cite web |url=https://www.computerhope.com/issues/ch001399.htm |title=Desktop computer vs. Laptop computer |date=2019-12-30 |website=Computer Hope |access-date=2020-01-15}}</ref> Laptops contain the keyboard, display, and processor in one case. The monitor in the folding upper cover of the case can be closed for transportation to protect the screen and keyboard.  Instead of a mouse, laptops may have a [[Touchpad|touchpad]] or [[Engineering:Pointing stick|pointing stick]].
+*[[Engineering:Tablet computer|Tablets]] are portable computers that use a touch screen as the primary input device. Tablets generally weigh less and are smaller than laptops.{{cn|date=August 2024}} Some tablets include fold-out keyboards or offer connections to separate external keyboards. Some models of laptop computers have a detachable keyboard, which allows the system to be configured as a touch-screen tablet. They are sometimes called 2-in-1 detachable laptops or tablet-laptop hybrids.<ref>{{cite web | last=Cipriani | first=Jason |  title=Best 2-in-1 Detachable Laptops 2020: The Best Tablet-Laptop Hybrids | website=IGN | date=29 May 2020 | url=https://www.ign.com/articles/best-2-in-1-detachable-laptops | access-date=20 July 2020}}</ref>
+*[[Engineering:Mobile phone|Mobile phone]]s are designed to have an extended battery life and light weight, while having less functionality than larger computers. They have diverse hardware architecture, often including antennas, microphones, cameras, [[Engineering:GPS|GPS]] devices, and speakers. Power and data connections vary between phones.<ref>{{cite book |last1=Ahmed |first1=Rizwan |last2=Dharaskar |first2=Rajiv V. |title=Mobile Forensics: An Introduction from Indian Law Enforcement Perspective |date=2009 |publisher=Springer |isbn=978-3-642-00405-6 |page=177 |language=en}}</ref>
-[[Engineering:Tablet computer|Tablets]] are portable computers that use a touch screen as the primary input device. Tablets generally weigh less and are smaller than laptops.
+===Large-scale computers===
+[[File:Front Z9 2094.jpg|thumb|upright|An [[IBM System z9]] mainframe]]
+*A [[Mainframe computer|mainframe computer]] is a much larger computer that typically fills a room and may cost many hundreds or thousands of times as much as a personal computer. They are designed to perform large numbers of calculations for governments and large enterprises.
+*In the 1960s and 1970s, more and more departments started to use cheaper and dedicated systems for specific purposes like [[Process control|process control]] and [[Organization:Laboratory automation|laboratory automation]]. A [[Minicomputer|minicomputer]], or colloquially '''mini''', is a class of smaller [[Computer|computer]]s that was developed in the mid-1960s<ref>{{cite book|editor-last1=Henderson|editor-first1=Rebecca M.|editor-last2=Newell|editor-first2=Richard G.|title=Accelerating energy innovation : insights from multiple sectors|date=2011|publisher=University of Chicago Press|location=Chicago|isbn=978-0226326832|page=180}}</ref><ref>{{cite book |last1=Huang |first1=Han-Way |title=The Atmel AVR microcontroller : MEGA and XMEGA in assembly and C |date=2014 |publisher=Delmar Cengage Learning |isbn=978-1133607298 |location=Australia; United Kingdom |page=4}}</ref> and sold for much less than mainframe<ref>{{cite book|last1=Estabrooks|first1=Maurice|title=Electronic technology, corporate strategy, and world transformation |url=https://archive.org/details/electronictechno0000esta |url-access=registration|date=1995|publisher=Quorum Books|location=Westport, Conn.|isbn=0899309690|page=[https://archive.org/details/electronictechno0000esta/page/53 53]}}</ref> and mid-size computers from [[Company:IBM|IBM]] and its direct competitors.
+*[[Supercomputer]]s can cost hundreds of millions of dollars. They are designed to maximize performance in [[Floating-point arithmetic|floating-point arithmetic]] and execute batch programs that may take weeks to complete. Due to the need for efficient communication between [[Parallel computing|parallel programs]], the speed of the internal network is a critical priority.{{sfn|Hennessy |Patterson|2011|p=8}}
+*Warehouse scale computers are larger versions of cluster computers that came into fashion with [[Software as a service|software as a service]] provided via the internet. Their design is intended to minimize cost per operation and power usage, as they can cost over $100 million for a warehouse and the computers that go inside (the computers must be replaced every few years). Although availability is crucial for SaaS products, the software is designed to compensate for availability failures—unlike supercomputers.{{sfn|Hennessy |Patterson|2011|p=8}}
-Some tablets include fold-out keyboards or offer connections to separate external keyboards. Some models of laptop computers have a detachable keyboard, which allows the system to be configured as a touch-screen tablet. They are sometimes called "2-in-1 detachable laptops" or "tablet-laptop hybrids".<ref>{{cite web | last=Cipriani | first=Jason |  title=Best 2-in-1 Detachable Laptops 2020: The Best Tablet-Laptop Hybrids | website=IGN | date=29 May 2020 | url=https://www.ign.com/articles/best-2-in-1-detachable-laptops | access-date=20 July 2020}}</ref>
+===Virtual hardware===
+Virtual hardware is software that mimics the function of hardware; it is commonly used in infrastructure as a Service (IaaS) and platform as a Service (PaaS).{{sfn|Wang|2021|pp=1, 3}}
-====Case====
+===Embedded system===
+Embedded systems have the most variation in their processing power and cost: from an 8-bit processor that could cost less than USD$0.10, to higher-end processors capable of billions of operations per second and costing over USD$100. Cost is a particular concern with these systems, with designers often choosing the cheapest option that satisfies the performance requirements.{{sfn|Hennessy |Patterson|2011|pp=8-9}}
+==Components==
+===Case===
 {{Main|Engineering:Computer case}}
-The computer case encloses most of the components of the system. It provides mechanical support and protection for internal elements such as the motherboard, disk drives, and power supplies, and controls and directs the flow of cooling air over internal components. The case is also part of the system to control electromagnetic interference radiated by the computer and protects internal parts from electrostatic discharge. Large tower cases provide space for multiple disk drives or other peripherals and usually stand on the floor, while desktop cases provide less expansion room. All-in-one style designs include a video display built into the same case. Portable and laptop computers require cases that provide impact protection for the unit. Hobbyists may decorate the cases with colored lights, paint, or other features, in an activity called [[Engineering:Case modding|case modding]].
+A computer case encloses most of the components of a desktop computer system. It provides mechanical support and protection for internal elements such as the motherboard, disk drives, and power supply, and controls and directs the flow of cooling air over internal components. The case is also part of the system to control electromagnetic interference radiated by the computer and protects internal parts from electrostatic discharge. Large tower cases provide space for multiple disk drives or other peripherals and usually stand on the floor, while desktop cases provide less expansion room. All-in-one style designs include a video display built into the same case. Portable and laptop computers require cases that provide impact protection for the unit. Hobbyists may decorate the cases with colored lights, paint, or other features, in an activity called [[Engineering:Case modding|case modding]].
-====Power supply====
+===Power supply===
+Most personal computer power supply units meet the ATX standard and convert from [[Physics:Alternating current|alternating current]] (AC) at between 120 and 277 volts provided from a power outlet to [[Physics:Direct current|direct current]] (DC) at a much lower voltage: typically 12, 5, or 3.3 volts.<ref>{{cite book |last1=Wilson |first1=Kevin |title=Exploring Computer Hardware: The Illustrated Guide to Understanding Computer Hardware, Components, Peripherals & Networks |date=2022 |publisher=Elluminet Press |isbn=978-1-913151-73-7 |url=https://books.google.com/books?id=RaN4EAAAQBAJ&dq=%22power+supply+(PSU)+converts+high%22&pg=PT111 |language=en}}</ref>
-A power supply unit (PSU) converts alternating current (AC) electric power to low-voltage direct current (DC) power for the computer. Laptops can run on built-in rechargeable battery.<ref>{{cite web |url=http://www.computerhope.com/issues/ch001236.htm |title=How long should a laptop battery last? |publisher=Computer Hope |access-date=9 December 2013 |url-status=live |archive-url=https://web.archive.org/web/20131221220614/http://www.computerhope.com/issues/ch001236.htm |archive-date=21 December 2013 |df=dmy-all }}</ref> The PSU typically uses a [[Engineering:Switched-mode power supply|switched-mode power supply]] (SMPS), with [[Engineering:Power MOSFET|power MOSFET]]s (power metal–oxide–semiconductor field-effect transistors) used in the converters and regulator circuits of the SMPS.<ref name="tomshardware">{{cite web |last1=Harding |first1=Scharon |title=What Is a MOSFET? A Basic Definition |url=https://www.tomshardware.com/uk/reviews/mosfet-defintion-transistor-pc-motherboard-psu-explained,6343.html |website=[[Tom's Hardware]] |access-date=7 November 2019 |date=September 17, 2019}}</ref>
+===Motherboard===
+{{Main|Engineering:Motherboard}}
-====Motherboard====
 [[File:Computer-motherboard.jpg|thumb|Computer motherboard]]
-{{Main|Engineering:Motherboard}}
 The motherboard is the main component of a computer. It is a board with [[Engineering:Integrated circuit|integrated circuit]]ry that connects the other parts of the computer including the CPU, the RAM, the disk drives ([[Engineering:CD|CD]], [[Engineering:DVD|DVD]], hard disk, or any others) as well as any peripherals connected via the ports or the [[Engineering:Expansion slot|expansion slot]]s. The [[Engineering:Integrated circuit|integrated circuit]] (IC) chips in a computer typically contain billions of tiny metal–oxide–semiconductor field-effect transistors (MOSFETs).<ref name="computerhistory2018">{{cite web |title=13 Sextillion & Counting: The Long & Winding Road to the Most Frequently Manufactured Human Artifact in History |url=https://www.computerhistory.org/atchm/13-sextillion-counting-the-long-winding-road-to-the-most-frequently-manufactured-human-artifact-in-history/ |date=April 2, 2018 |website=Computer History Museum |access-date=28 July 2019}}</ref>
 Components directly attached to or to part of the motherboard include:
-* The [[Central processing unit|CPU]] (central processing unit), which performs most of the calculations that enable a computer to function, and is referred to as the brain of the computer.  It takes program instructions from [[Random-access memory|random-access memory]] (RAM), interprets and processes them and then sends back results so that the relevant components can carry out the instructions. The CPU is a [[Engineering:Microprocessor|microprocessor]], which is [[Engineering:Semiconductor device fabrication|fabricated]] on a metal–oxide–semiconductor (MOS) [[Engineering:Integrated circuit|integrated circuit]] (IC) chip. It is usually cooled by a heatsink and fan, or water-cooling system. Many newer CPUs include an on-die [[Graphics processing unit|graphics processing unit]] (GPU). The clock speed of the CPU governs how fast it executes instructions and is measured in GHz; typical values lie between 1&nbsp;GHz and 5&nbsp;GHz. Many modern computers have the option to overclock the CPU which enhances performance at the expense of greater thermal output and thus a need for improved cooling.
+* At least one CPU (central processing unit), which performs the majority of computational tasks required for a computer to operate.{{sfn|Wang|2021|p=8}} Often described informally as the ''brain'' of the computer,{{sfn|Wang|2021|p=9}} the CPU fetches program instructions from [[Random-access memory|random-access memory]] (RAM), decodes and executes them, then returns results for further processing by other components. This process is known as the [[Instruction cycle|instruction cycle]]. Modern CPUs are [[Engineering:Microprocessor|microprocessor]]s fabricated on a metal–oxide–semiconductor (MOS) [[Engineering:Integrated circuit|integrated circuit]] (IC) using advanced [[Engineering:Semiconductor device fabrication|semiconductor device fabrication]] techniques, often employing [[Engineering:Photolithography|photolithography]]. They are typically cooled using a heatsink and [[Engineering:Computer fan|fan]] or a [[Physics:Liquid cooling|liquid-cooling system]]. Many contemporary CPUs integrate an on-die [[Graphics processing unit|graphics processing unit]] (GPU), eliminating the need for a discrete GPU in basic systems. CPU performance is influenced by clock speed—measured in gigahertz (GHz)—with common consumer processors ranging from 1&nbsp;GHz to 5&nbsp;GHz.{{cn|date=August 2024}} Additionally, there is a growing trend toward [[Multi-core processor|multi-core designs]], where multiple processing cores are included on a single chip, enabling greater [[Parallel computing|parallelism]] and improved multitasking performance.{{sfn|Wang|2021|p=9}}
-* The [[Engineering:Chipset|chipset]], which includes the north bridge, mediates communication between the CPU and the other components of the system, including main memory; as well as south bridge, which is connected to the north bridge, and supports auxiliary interfaces and buses; and, finally, a Super I/O chip, connected through the south bridge, which supports the slowest and most legacy components like [[Serial port|serial port]]s, hardware monitoring and fan control.
+*The internal bus connects the CPU to main memory via multiple communication lines—typically 50 to 100—divided into address, data, and control buses, each handling specific types of signals.{{sfn|Wang|2021|p=75}} Historically, parallel buses were dominant, but in the twenty-first century, high-speed serial buses (often using serializer/deserializer (SerDes) technology) have largely replaced them, enabling greater data throughput over fewer physical connections. Examples include [[Engineering:PCI Express|PCI Express]] and [[Engineering:USB|USB]].{{sfn|Wang|2021|p=78}} In systems with multiple processors, an interconnect bus is used, traditionally coordinated by a northbridge chip, which links the CPU, memory, and high-speed peripherals such as [[Engineering:Peripheral Component Interconnect|PCI]]. The southbridge handles communication with slower I/O devices such as storage and USB ports.{{sfn|Wang|2021|p=90}} However, in modern architectures like [[Intel QuickPath Interconnect]] or AMD Ryzen-based systems, these functions are increasingly integrated into the CPU itself, forming a [[System on a chip|system on a chip]] (SoC)-like design.
-*[[Random-access memory]] (RAM), which stores the code and data that are being actively accessed by the CPU. For example, when a web browser is opened on the computer it takes up memory; this is stored in the RAM until the web browser is closed. It is typically a type of dynamic RAM (DRAM), such as synchronous DRAM (SDRAM), where MOS memory chips store data on [[Memory cell (computing)|memory cells]] consisting of MOSFETs and [[Engineering:MOS capacitor|MOS capacitor]]s. RAM usually comes on dual in-line memory modules (DIMMs) in the sizes of 2GB, 4GB, and 8GB, but can be much larger.
+*[[Random-access memory]] (RAM) stores code and data actively used by the CPU, organized in a [[Memory hierarchy|memory hierarchy]] optimized for access speed and predicted reuse. At the top of this hierarchy are [[Processor register|registers]], located within the CPU core, offering the fastest access but extremely limited capacity.{{sfn|Wang|2021|p=47}} Below registers are multiple levels of cache memory—L1, L2, and sometimes L3—typically implemented using [[Static random-access memory|static random-access memory]] (SRAM). Caches have greater capacity than registers but less than main memory, and while slower than registers, they are significantly faster than [[Dynamic random-access memory|dynamic random-access memory]] (DRAM), which is used for main RAM.{{sfn|Wang|2021|pp=49–50}} Caching improves performance by [[Prefetching|prefetching]] frequently used data, thereby reducing [[Memory latency|memory latency]].{{sfn|Wang|2021|pp=49–50}}{{sfn|Hennessy|Patterson|2011|p=45}} When data is not found in the cache (a cache miss), it is retrieved from main memory. RAM is volatile, meaning its contents are lost when the system loses power.{{sfn|Wang|2021|p=54}} In modern systems, DRAM is often of the DDR SDRAM type, such as DDR4 or DDR5.
-*[[Read-only memory]] (ROM), which stores the [[BIOS]] that runs when the computer is powered on or otherwise begins execution, a process known as Bootstrapping, or "[[Booting|booting]]" or "booting up". The ROM is typically a [[Nonvolatile BIOS memory|nonvolatile BIOS memory]] chip, which stores data on [[Engineering:Floating-gate MOSFET|floating-gate MOSFET]] memory cells.
+*Permanent storage or non-volatile memory is typically higher capacity and cheaper than memory, but takes much longer to access. Historically, such storage was typically provided in the form of a hard drive, but solid-state drives (SSD) are becoming cheaper and are much faster, thus leading to their increasing adoption. USB drives and network or cloud storage are also options.{{sfn|Wang|2021|pp=55–56}}
-** The [[BIOS]] (Basic Input Output System) includes boot [[Firmware|firmware]] and power management firmware. Newer motherboards use Unified Extensible Firmware Interface (UEFI) instead of BIOS.
+*[[Read-only memory]] (ROM) contains firmware such as the [[BIOS]] (Basic Input/Output System), which initializes hardware during the boot process—known as [[Booting|booting]] or bootstrapping—when the computer is powered on.{{cn|date=August 2024}} This firmware is stored in a non-volatile memory chip, traditionally ROM or [[Flash memory|flash memory]], allowing updates in modern systems via firmware update.{{sfn|Wang|2021|p=55}}
-*[[Engineering:Bus (computing)|Buses]] that connect the CPU to various internal components and to expand cards for graphics and sound.
+** The BIOS manages essential functions, including boot sequence and power management through the [[ACPI]] standard. However, most modern motherboards have transitioned to the Unified Extensible Firmware Interface (UEFI), which offers enhanced capabilities, faster startup times, support for [[GUID Partition Table]] (GPT), and secure boot features.
 * The [[Engineering:CMOS|CMOS]] (complementary MOS) [[Physics:Electric battery|battery]], which powers the CMOS memory for date and time in the BIOS chip. This battery is generally a watch battery.
-* The [[Engineering:Video card|video card]] (also known as the graphics card), which processes computer graphics. More powerful graphics cards are better suited to handle strenuous tasks, such as playing intensive video games or running [[Computer graphics|computer graphics]] software. A video card contains a [[Graphics processing unit|graphics processing unit]] (GPU) and video memory (typically a type of SDRAM), both fabricated on [[Engineering:MOS integrated circuit|MOS integrated circuit]] (MOS IC) chips.
+*[[Engineering:Power MOSFET|Power MOSFET]]s make up the [[Engineering:Voltage regulator module|voltage regulator module]] (VRM), which controls how much [[Physics:Voltage|voltage]] other hardware components receive.<ref name="tomshardware">{{cite web |last1=Harding |first1=Scharon |title=What Is a MOSFET? A Basic Definition |url=https://www.tomshardware.com/uk/reviews/mosfet-defintion-transistor-pc-motherboard-psu-explained,6343.html |website=[[Tom's Hardware]] |access-date=7 November 2019 |date=September 17, 2019}}</ref>
-*[[Engineering:Power MOSFET|Power MOSFET]]s make up the [[Engineering:Voltage regulator module|voltage regulator module]] (VRM), which controls how much [[Physics:Voltage|voltage]] other hardware components receive.<ref name="tomshardware"/>
-====Expansion cards====
+===Expansion cards===
 {{Main|Engineering:Expansion card}}
-An [[Engineering:Expansion card|expansion card]] in computing is a printed circuit board that can be inserted into an expansion slot of a computer motherboard or backplane to add functionality to a computer system via the expansion bus. Expansion cards can be used to obtain or expand on features not offered by the motherboard.
+An [[Engineering:Expansion card|expansion card]] in computing is a printed circuit board that can be inserted into an expansion slot of a computer motherboard or backplane to add functionality to a computer system via the expansion bus. Expansion cards can be used to obtain or expand on features not offered by the motherboard.<ref>{{cite web |title=What is an Expansion Card? |url=https://www.lenovo.com/us/en/glossary/expansion-card/ |website=Lenovo |access-date=17 February 2025}}</ref> Using expansion cards for a video processor used to be common, but modern computers are more likely to instead have a GPU integrated into the motherboard.{{sfn|Wang|2021|p=121}}
-====Storage devices====
+===Input/output===
-{{Main|Computer data storage}}
-A storage device is any computing hardware and [[Digital media|digital media]] that is used for storing, porting and extracting data files and objects. It can hold and store information both temporarily and permanently and can be internal or external to a computer, server or any similar computing device. Data storage is a core function and fundamental component of computers. Dedicated storage devices include RAIDs and [[Engineering:Tape library|tape libraries]].
-=====Fixed media=====
-Data is stored by a computer using a variety of media. [[Engineering:Hard disk drive|Hard disk drive]]s (HDDs) are found in virtually all older computers, due to their high capacity and low cost, but [[Solid-state drive|solid-state drive]]s (SSDs) are faster and more power efficient, although currently more expensive than hard drives in terms of dollar per gigabyte,<ref>{{cite web|last1=Domingo|first1=Joel|title=SSD vs. HDD: What's the Difference?|url=https://www.pcmag.com/article2/0,2817,2404258,00.asp|publisher=PCMag|access-date=24 March 2017|url-status=live|archive-url=https://web.archive.org/web/20170319184712/http://www.pcmag.com/article2/0,2817,2404258,00.asp|archive-date=19 March 2017|df=dmy-all}}</ref> so are often found in personal computers built post-2007.<ref>{{cite magazine|last1=Edwards|first1=Benj|title=Evolution of the Solid-State Drive|url=http://www.pcworld.com/article/246617/storage/evolution-of-the-solid-state-drive.html#slide13|magazine=PCWorld|access-date=24 March 2017|url-status=live|archive-url=https://web.archive.org/web/20170325201429/http://www.pcworld.com/article/246617/storage/evolution-of-the-solid-state-drive.html#slide13|archive-date=25 March 2017|df=dmy-all|date=2012-01-17}}</ref> SSDs use [[Flash memory|flash memory]], which stores data on MOS memory chips consisting of [[Engineering:Floating-gate MOSFET|floating-gate MOSFET]] [[Memory cell (computing)|memory cells]]. Some systems may use a [[Engineering:Disk array controller|disk array controller]] for greater performance or reliability.
-=====Removable media=====
-To transfer data between computers, an external [[Flash memory|flash memory]] device (such as a [[Memory card|memory card]] or [[Engineering:USB flash drive|USB flash drive]]) or [[Engineering:Optical disc|optical disc]] (such as a [[CD-ROM]], DVD-ROM or BD-ROM) may be used. Their usefulness depends on being readable by other systems; the majority of machines have an optical disk drive (ODD), and virtually all have at least one Universal Serial Bus (USB) port. Additionally, USB sticks are typically pre-formatted with the [[FAT32]] file system, which is widely supported across [[Operating system|operating system]]s.
-====Input and output peripherals====
 {{Main|Engineering:Peripheral}}
-[[Input device|Input]] and [[Output device|output]] devices are typically housed externally to the main computer chassis. The following are either standard or very common to many computer systems.
+Most computers also have an external data bus to connect peripheral devices to the motherboard. Most commonly, Universal Serial Bus (USB) is used.{{sfn|Wang|2021|p=74}} Unlike the internal bus, the external bus is connected using a bus controller that allows the peripheral system to operate at a different speed from the CPU.{{sfn|Wang|2021|p=74}} [[Input device|Input]] and [[Output device|output]] devices are used to receive data from the external world or write data, respectively. Common examples include keyboards and [[Computer mouse|mice]] (input) and displays and printers (output). [[Engineering:Network interface controller|Network interface controller]]s are used to access the Internet.{{sfn|Wang|2021|p=7}} USB ports also allow power to connected devices—a standard USB supplies power at 5 volts and up to 500 milliamps (2.5 [[Watt|watt]]s), while powered USB ports with additional pins may allow the delivery of more power—up to 6 [[Ampere|amps]] at 24v.{{sfn|Wang|2021|p=116}}
-=====Input device=====
-Input devices allow the user to enter information into the system, or control its operation. Most personal computers have a mouse and keyboard, but laptop systems typically use a [[Touchpad|touchpad]] instead of a mouse. Other input devices include [[Webcam|webcam]]s, [[Microphone|microphone]]s, [[Engineering:Joystick|joystick]]s, and [[Social:Image scanner|image scanner]]s.
-=====Output device=====
-[[Output device]]s are designed around the senses of human beings. For example, [[Engineering:Computer monitor|monitors]] display text that can be read, speakers produce sound that can be heard.<ref>{{cite book |title=PC hardware : a beginner's guide |date=2001 |publisher=Osborne/McGraw-Hill |isbn=9780072129908 |pages=[https://archive.org/details/pchardwarebeginn00gils/page/20 20] |url=https://archive.org/details/pchardwarebeginn00gils/page/20 }}</ref> Such devices also could include [[Engineering:Printer (computing)|printer]]s or a [[Engineering:Braille embosser|Braille embosser]].
-===Mainframe computer===
-A [[Mainframe computer|mainframe computer]] is a much larger computer that typically fills a room and may cost many hundreds or thousands of times as much as a personal computer. They are designed to perform large numbers of calculations for governments and large enterprises.[[File:Front Z9 2094.jpg|thumb|upright|An IBM System z9 mainframe]]
-===Departmental computing===
-{{Main|Minicomputer}}
-In the 1960s and 1970s, more and more departments started to use cheaper and dedicated systems for specific purposes like [[Process control|process control]] and [[Organization:Laboratory automation|laboratory automation]]. A '''minicomputer''', or colloquially '''mini''', is a class of smaller [[Computer|computer]]s that was developed in the mid-1960s<ref>{{cite book|editor-last1=Henderson|editor-first1=Rebecca M.|editor-last2=Newell|editor-first2=Richard G.|title=Accelerating energy innovation : insights from multiple sectors|date=2011|publisher=University of Chicago Press|location=Chicago|isbn=978-0226326832|page=180}}</ref><ref>{{cite book|last1=Huang|first1=Han-Way|title=The atme AVR microcontroller : MEGA and XMEGA in assembly and C|date=2014|publisher=Delmar Cengage Learning|location=Australia; United Kingdom|isbn=978-1133607298|page=4}}</ref> and sold for much less than [[Mainframe computer|mainframe]]<ref>{{cite book|last1=Estabrooks|first1=Maurice|title=Electronic technology, corporate strategy, and world transformation |url=https://archive.org/details/electronictechno0000esta |url-access=registration|date=1995|publisher=Quorum Books|location=Westport, Conn.|isbn=0899309690|page=[https://archive.org/details/electronictechno0000esta/page/53 53]}}</ref> and mid-size computers from [[Company:IBM|IBM]] and its direct competitors.
-===Supercomputer===
-{{Main|Supercomputer}}
-A [[Supercomputer|supercomputer]] is superficially similar to a mainframe but is instead intended for extremely demanding computational tasks. {{As of|November 2021}}, the fastest supercomputer on the [[TOP500]] supercomputer list is [[Fugaku (supercomputer)|Fugaku]], in Japan, with a LINPACK benchmark score of 415 PFLOPS, superseding the second fastest, Summit, in the United States, by around 294 PFLOPS.
-The term supercomputer does not refer to a specific technology. Rather it indicates the fastest computations available at any given time. In mid-2011, the fastest supercomputers boasted speeds exceeding one petaflop, or 1 quadrillion (10^15 or 1,000 trillion) floating-point operations per second.
-Supercomputers are fast but extremely costly, so they are generally used by large organizations to execute computationally demanding tasks involving large data sets. Supercomputers typically run military and scientific applications. Although costly, they are also being used for commercial applications where huge amounts of data must be analyzed. For example, large banks employ supercomputers to calculate the risks and returns of various investment strategies, and healthcare organizations use them to analyze giant databases of patient data to determine optimal treatments for various diseases and problems incurring to the country.
-==Hardware upgrade==
-When using computer hardware, an [[Upgrade|upgrade]] means adding new or additional hardware to a computer that improves its performance, increases its capacity, or adds new features. For example, a user could perform a hardware upgrade to replace the hard drive with a faster one or a solid state drive (SSD) to get a boost in performance. The user may also install more [[Random-access memory|Random Access Memory]] (RAM) so the computer can store additional temporary data, or retrieve such data at a faster rate. The user may add a USB 3.0 [[Engineering:Expansion card|expansion card]] to fully use USB 3.0 devices, or could upgrade the Graphics Processing Unit (GPU) for cleaner, more advanced graphics, or more [[Engineering:Computer monitor|monitors]]. Performing such hardware upgrades may be necessary for aged computers to meet a new, or updated program's system requirements.
-In large organizations, hardware upgrades are handled by [[Network administrator|administrators]] who are also in charge of keeping [[Computer network|networks]] running smoothly. They replace network devices like [[Server (computing)|servers]], [[Engineering:Router (computing)|routers]] and storage devices based on new demands and capacities.
 ==Sales==
-Global revenue from computer hardware in 2023 reached $705.17 billion.<ref>{{Cite web |title=Computer Hardware Market Size, Trends and Global Forecast To 2032 |url=https://www.thebusinessresearchcompany.com/report/computer-hardware-global-market-report#:~:text=The%20global%20computer%20hardware%20market,least%20in%20the%20short%20term. |access-date=2023-03-03 |website=www.thebusinessresearchcompany.com}}</ref>
+Global revenue from computer hardware in 2023 reached $705.17 billion.<ref>{{Cite web |title=Computer Hardware Market Size, Trends and Global Forecast To 2032 |url=https://www.thebusinessresearchcompany.com/report/computer-hardware-global-market-report#:~:text=The%20global%20computer%20hardware%20market,least%20in%20the%20short%20term. |access-date=2023-03-03 |website=The Business Research Company }}</ref>
 ==Recycling==
 {{main|Computer recycling}}
-Because computer parts contain [[Hazard|hazard]]ous materials, there is a growing movement to recycle old and outdated parts.<ref>{{Cite news|url=http://www.digitaltrends.com/computing/how-to-recycle-your-old-computer/|title=How to recycle your old computer|date=2016-12-18|work=Digital Trends|access-date=2017-04-18|language=en-US|url-status=live|archive-url=https://web.archive.org/web/20170417055533/http://www.digitaltrends.com/computing/how-to-recycle-your-old-computer/|archive-date=17 April 2017|df=dmy-all}}</ref> Computer hardware contain dangerous chemicals such as lead, mercury, nickel, and cadmium. According to the EPA these e-wastes have a harmful effect on the [[Earth:Natural environment|environment]] unless they are disposed of properly. Making hardware requires energy, and [[Physics:Recycling|recycling]] parts will reduce air pollution, water pollution, as well as greenhouse gas emissions.<ref>{{Cite web|url=https://www.newtechrecycling.com/disposal/computer-recycling/computer-recycling.html|title=Newtech Recycling Specializes in Computer Disposal, Laptop Disposal, Desktop Disposal Mainframe Disposal and Server Disposal|website=Newtech Recycling, Inc.|archive-url=https://web.archive.org/web/20170329142805/https://www.newtechrecycling.com/disposal/computer-recycling/computer-recycling.html|archive-date=29 March 2017|url-status=dead|access-date=2017-04-18|df=dmy-all}}</ref> Disposing unauthorized computer equipment is in fact illegal. Legislation makes it mandatory to [[Physics:Recycling|recycle]] computers through the [[Social:Government|government]] approved facilities. Recycling a computer can be made easier by taking out certain reusable parts. For example, the [[Random-access memory|RAM]], DVD drive, the [[Graphics hardware|graphics card]], [[Engineering:Hard disk drive|hard drive]] or [[Solid-state drive|SSD]], and other similar removable parts can be reused.
+Because computer parts contain [[Hazard|hazard]]ous materials, there is a growing movement to recycle old and outdated devices.<ref>{{Cite news|url=http://www.digitaltrends.com/computing/how-to-recycle-your-old-computer/|title=How to recycle your old computer|date=2016-12-18|work=Digital Trends|access-date=2017-04-18|language=en-US|url-status=live|archive-url=https://web.archive.org/web/20170417055533/http://www.digitaltrends.com/computing/how-to-recycle-your-old-computer/|archive-date=17 April 2017|df=dmy-all}}</ref> Computer hardware contains hazardous substances such as lead, mercury, nickel, and cadmium. According to the EPA, these e-wastes negatively affect the [[Earth:Natural environment|environment]] if not disposed of properly. Hardware manufacturing also requires significant energy, while [[Physics:Recycling|recycling]] components helps reduce air and water pollution as well as greenhouse gas emissions.<ref>{{Cite web|url=https://www.newtechrecycling.com/disposal/computer-recycling/computer-recycling.html|title=Newtech Recycling Specializes in Computer Disposal, Laptop Disposal, Desktop Disposal Mainframe Disposal and Server Disposal|website=Newtech Recycling, Inc.|archive-url=https://web.archive.org/web/20170329142805/https://www.newtechrecycling.com/disposal/computer-recycling/computer-recycling.html|archive-date=29 March 2017|url-status=dead|access-date=2017-04-18|df=dmy-all}}</ref> In many regions, improper disposal of computer equipment is illegal, and legislation requires recycling through [[Social:Government|government]]-approved facilities. Recycling can be facilitated by removing reusable parts such as RAM, DVD drives, [[Engineering:Graphics card|graphics card]]s, hard drives, SSDs, and other similar components.
-Many materials used in computer hardware can be recovered by recycling for use in future production. Reuse of [[Chemistry:Tin|tin]], [[Chemistry:Silicon|silicon]], [[Chemistry:Iron|iron]], [[Chemistry:Aluminum|aluminum]], and a variety of plastics that are present in bulk in computers or other electronics can reduce the costs of constructing new systems. Components frequently contain [[Chemistry:Copper|copper]], [[Chemistry:Gold|gold]], [[Chemistry:Tantalum|tantalum]],<ref>{{Cite web|url=https://www.raci.org.au/document/item/488|title=TANTALUM|last=Robert-Tissot|first=Sarah|date=2011|website=Royal Australian Chemical instatute|access-date=March 3, 2019|archive-date=26 February 2017|archive-url=https://web.archive.org/web/20170226021016/https://www.raci.org.au/document/item/488|url-status=dead}}</ref><ref>{{Cite web|url=https://minerals.usgs.gov/minerals/pubs/commodity/niobium/mcs-2019-tanta.pdf|title=TANTALUM|last=Padilla|first=Abraham|date=February 2019|website=United states geological survey|access-date=March 3, 2019}}</ref> [[Chemistry:Silver|silver]], [[Chemistry:Platinum|platinum]], [[Chemistry:Palladium|palladium]], and [[Chemistry:Lead|lead]] as well as other valuable materials suitable for reclamation.<ref>{{Cite web|url=https://pubs.usgs.gov/fs/fs060-01/fs060-01.pdf|title=Obsolete Computers, "Gold Mine," or High-Tech Trash? Resource Recovery from Recycling|last=Bleiwas|first=D|date=July 2001|website=USGS|access-date=March 4, 2019}}</ref><ref>{{Cite web|url=https://www.thebalancesmb.com/electronic-devices-source-of-metals-for-recyclers-2877986|title=Electronic Devices a Rich Source of Precious Metals for Recyclers|last=LeBlanc|first=Rick|website=The Balance Small Business|language=en|access-date=2019-03-04}}</ref>
+Many materials used in computer hardware can be recovered through recycling for use in future production. The reuse of [[Chemistry:Tin|tin]], [[Chemistry:Silicon|silicon]], [[Chemistry:Iron|iron]], [[Chemistry:Aluminum|aluminum]], and various plastics commonly found in computers and other electronics helps reduce the costs of manufacturing new systems. Hardware components also frequently contain [[Chemistry:Copper|copper]], [[Chemistry:Gold|gold]], [[Chemistry:Tantalum|tantalum]],<ref>{{Cite web|url=https://www.raci.org.au/document/item/488|title=TANTALUM|last=Robert-Tissot|first=Sarah|date=2011|website=Royal Australian Chemical Institute|access-date=March 3, 2019|archive-date=26 February 2017|archive-url=https://web.archive.org/web/20170226021016/https://www.raci.org.au/document/item/488|url-status=dead}}</ref><ref>{{Cite web|url=https://minerals.usgs.gov/minerals/pubs/commodity/niobium/mcs-2019-tanta.pdf|title=TANTALUM|last=Padilla|first=Abraham|date=February 2019|website=United States Geological Survey|access-date=March 3, 2019}}</ref> [[Chemistry:Silver|silver]], [[Chemistry:Platinum|platinum]], [[Chemistry:Palladium|palladium]], and [[Chemistry:Lead|lead]], along with other valuable materials suitable for reclamation.<ref>{{Cite web|url=https://pubs.usgs.gov/fs/fs060-01/fs060-01.pdf|title=Obsolete Computers, "Gold Mine," or High-Tech Trash? Resource Recovery from Recycling|last=Bleiwas|first=D|date=July 2001|website=USGS|access-date=March 4, 2019}}</ref><ref>{{Cite web|url=https://www.thebalancesmb.com/electronic-devices-source-of-metals-for-recyclers-2877986|title=Electronic Devices a Rich Source of Precious Metals for Recyclers|last=LeBlanc|first=Rick|website=The Balance Small Business|language=en|access-date=2019-03-04}}</ref>
 ===Toxic computer components===
-The [[Central processing unit|central processing unit]] contains many toxic materials. It contains lead and chromium in the metal plates. Resistors, semiconductors, infrared detectors, stabilizers, cables, and wires contain cadmium. The circuit boards in a computer contain mercury, and chromium.<ref>{{Cite news|url=http://smallbusiness.chron.com/toxic-components-computers-monitors-69693.html|title=The Toxic Components of Computers and Monitors|access-date=2017-04-26|language=en|url-status=live|archive-url=https://web.archive.org/web/20170427192255/http://smallbusiness.chron.com/toxic-components-computers-monitors-69693.html|archive-date=27 April 2017|df=dmy-all}}</ref> When these types of materials, and chemicals are disposed improperly will become hazardous for the environment.
+The [[Central processing unit|central processing unit]] contains several toxic materials. It may include lead and chromium in metal plates. Resistors, semiconductors, infrared detectors, stabilizers, cables, and wires can contain cadmium, while computer circuit boards may also contain mercury and chromium.<ref>{{Cite news|url=http://smallbusiness.chron.com/toxic-components-computers-monitors-69693.html|title=The Toxic Components of Computers and Monitors|access-date=2017-04-26|language=en|url-status=live|archive-url=https://web.archive.org/web/20170427192255/http://smallbusiness.chron.com/toxic-components-computers-monitors-69693.html|archive-date=27 April 2017|df=dmy-all}}</ref> Improper disposal of these materials and chemicals can pose serious hazards to the environment.
 ===Environmental effects===
-According to the United States Environmental Protection Agency only around 15% of the e-waste actually is recycled. When e-waste byproducts leach into groundwater, are burned, or get mishandled during recycling, it causes harm. Health problems associated with such toxins include impaired mental development, cancer, and damage to the lungs, liver, and kidneys.<ref>{{Cite web|url=http://www.electronicstakeback.com/2015/05/28/whats-going-on-with-electronic-waste/|title=What's Going On with Electronic Waste? – Electronics TakeBack Coalition|access-date=2017-04-26|url-status=live|archive-url=https://web.archive.org/web/20170427103038/http://www.electronicstakeback.com/2015/05/28/whats-going-on-with-electronic-waste/|archive-date=27 April 2017|df=dmy-all}}</ref> That is why even wires have to be recycled. Different companies have different techniques to recycle a wire. The most popular one is the grinder that separates the copper wires from the plastic/rubber casing. When the processes are done there are two different piles left; one containing the copper powder, and the other containing plastic/rubber pieces.<ref>{{Cite news|url=http://www.all-recycling-facts.com/wire-recycling.html|title=Wire Recycling|work=All-Recycling-Facts.com|access-date=2017-05-05|url-status=live|archive-url=https://web.archive.org/web/20170710232319/http://www.all-recycling-facts.com/wire-recycling.html|archive-date=10 July 2017|df=dmy-all}}</ref> Computer monitors, [[Computer mouse|mice]], and [[Computer keyboard|keyboards]] all have a similar way of being recycled. For example, first, each of the parts are taken apart then all of the inner parts get separated and placed into its own bin.<ref>{{Cite news|url=http://www.computerweekly.com/feature/Computer-equipment-recycling-Essential-Guide|title=Computer equipment recycling – Essential Guide|work=ComputerWeekly|access-date=2017-05-08|language=en-GB|url-status=live|archive-url=https://web.archive.org/web/20161221184215/http://www.computerweekly.com/feature/Computer-equipment-recycling-Essential-Guide/|archive-date=21 December 2016|df=dmy-all}}</ref>
+When e-waste byproducts leach into groundwater, are burned, or get mishandled during recycling, it causes harm. Health problems associated with such toxins include impaired mental development, cancer, and damage to the lungs, liver, and kidneys.<ref>{{Cite web|url=http://www.electronicstakeback.com/2015/05/28/whats-going-on-with-electronic-waste/|title=What's Going On with Electronic Waste? – Electronics TakeBack Coalition|access-date=2017-04-26|url-status=usurped|archive-url=https://web.archive.org/web/20170427103038/http://www.electronicstakeback.com/2015/05/28/whats-going-on-with-electronic-waste/|archive-date=27 April 2017|df=dmy-all}}</ref> Computer components contain many toxic substances, like [[Chemistry:Polychlorinated dibenzodioxins|dioxins]], [[Chemistry:Polychlorinated biphenyl|polychlorinated biphenyl]]s (PCBs), [[Chemistry:Cadmium|cadmium]], [[Chemistry:Chromium|chromium]], radioactive isotopes and [[Chemistry:Mercury (element)|mercury]]. Circuit boards contain considerable quantities of lead-tin solders that are more likely to leach into groundwater or create [[Earth:Air pollution|air pollution]] due to incineration.<ref name=":0">{{Cite web|url=https://computer.howstuffworks.com/discarded-old-computer1.htm|title=What Happens to your Discarded Old Computer?|last=Toothman|first=Jessika|website=HowStuffWorks|date=2 June 2008}}</ref>
-Computer components contain many toxic substances, like [[Chemistry:Polychlorinated dibenzodioxins|dioxins]], [[Chemistry:Polychlorinated biphenyl|polychlorinated biphenyl]]s (PCBs), [[Chemistry:Cadmium|cadmium]], [[Chemistry:Chromium|chromium]], [[Physics:Radionuclide|radioactive isotopes]] and [[Chemistry:Mercury (element)|mercury]]. Circuit boards contain considerable quantities of lead-tin solders that are more likely to leach into groundwater or create [[Earth:Air pollution|air pollution]] due to incineration. In US landfills, about 40% of the lead content levels are from e-waste.<ref name=":0">{{Cite web|url=https://computer.howstuffworks.com/discarded-old-computer1.htm|title=What Happens to your Discarded Old Computer?|last=Toothman|first=Jessika|website=HowStuffWorks|date=2 June 2008}}</ref> The processing (e.g. incineration and acid treatments) required to reclaim these precious substances may release, generate, or synthesize toxic byproducts.
 Recycling of computer hardware is considered environmentally friendly because it prevents hazardous waste, including [[Chemistry:Toxic heavy metal|heavy metals]] and carcinogens, from entering the atmosphere, landfill or waterways. While electronics consist a small fraction of total waste generated, they are far more dangerous. There is stringent legislation designed to enforce and encourage the sustainable disposal of appliances, the most notable being the Waste Electrical and Electronic Equipment Directive of the [[Social:European Union|European Union]] and the United States National Computer Recycling Act.<ref>National Computer Recycling Act of 2005, H.R. 425, 109th Cong. (2005–2006)</ref>
 ===Efforts for minimizing computer hardware waste===
-As computer hardware contain a wide number of metals inside, the United States Environmental Protection Agency (EPA) encourages the collection and recycling of computer hardware. "E-cycling", the recycling of computer hardware, refers to the donation, reuse, shredding and general collection of used electronics. Generically, the term refers to the process of collecting, brokering, disassembling, repairing and recycling the components or metals contained in used or discarded electronic equipment, otherwise known as electronic waste (e-waste). "E-cyclable" items include, but are not limited to: televisions, computers, microwave ovens, vacuum cleaners, telephones and cellular phones, stereos, and VCRs and DVDs just about anything that has a cord, light or takes some kind of battery.<ref name="epa-ewaste-presentation">{{Cite web |url=https://www.epa.gov/sites/production/files/2014-05/documents/overview.pdf |title=Broad Overview of E-Waste Management Policies in the U.S. |last= T. Gallo |first=Daniel |date=2013-07-15 |website=www.epa.gov |access-date=2020-01-17}}</ref>
+E-cycling, the recycling of computer hardware, refers to the donation, reuse, shredding and general collection of used electronics. Generically, the term refers to the process of collecting, brokering, disassembling, repairing and recycling the components or metals contained in used or discarded electronic equipment, otherwise known as electronic waste (e-waste). E-cyclable items include, but are not limited to: televisions, computers, microwave ovens, vacuum cleaners, telephones and cellular phones, stereos, and VCRs and DVDs just about anything that has a cord, light or takes some kind of battery.<ref name="epa-ewaste-presentation">{{Cite web |url=https://www.epa.gov/sites/default/files/2014-05/documents/overview.pdf |title=Broad Overview of E-Waste Management Policies in the U.S. |last= T. Gallo |first=Daniel |date=2013-07-15 |website=www.epa.gov |access-date=2020-01-17}}</ref>
-Some companies, such as [[Company:Dell|Dell]] and [[Company:Apple Inc.|Apple]], will recycle computers of their make or any other make. Otherwise, a computer can be donated to Computer Aid International which is an organization that recycles and refurbishes old computers for hospitals, schools, universities, etc.<ref>{{Cite news|url=https://www.theguardian.com/technology/askjack/2015/feb/19/how-safely-recycle-old-pcs-computers|title=How can I safely recycle my old PCs?|last=Schofield|first=Jack|date=2015-02-19|work=The Guardian|access-date=2017-04-26|language=en-GB|issn=0261-3077|url-status=live|archive-url=https://web.archive.org/web/20170427103349/https://www.theguardian.com/technology/askjack/2015/feb/19/how-safely-recycle-old-pcs-computers|archive-date=27 April 2017|df=dmy-all}}</ref>
+Some companies, such as [[Company:Dell|Dell]] and [[Company:Apple Inc.|Apple]], will recycle computers of their own make or any other make. Otherwise, a computer can be donated to Computer Aid International which is an organization that recycles and refurbishes old computers for hospitals, schools, universities, etc.<ref>{{Cite news|url=https://www.theguardian.com/technology/askjack/2015/feb/19/how-safely-recycle-old-pcs-computers|title=How can I safely recycle my old PCs?|last=Schofield|first=Jack|date=2015-02-19|work=The Guardian|access-date=2017-04-26|language=en-GB|issn=0261-3077|url-status=live|archive-url=https://web.archive.org/web/20170427103349/https://www.theguardian.com/technology/askjack/2015/feb/19/how-safely-recycle-old-pcs-computers|archive-date=27 April 2017|df=dmy-all}}</ref>
 ==See also==
@@ Line 145: / Line 136: @@
 ==References==
 {{reflist}}
+==Sources==
+*{{cite book |last1=Blum |first1=Edward K.  |title=Computer Science: The Hardware, Software and Heart of It |date=2011 |publisher=Springer Science & Business Media |isbn=978-1-4614-1168-0 |language=en}}
+*{{cite book |last1=Hennessy |first1=John L. |last2=Patterson |first2=David A. |title=Computer Architecture: A Quantitative Approach |date=2011 |publisher=Elsevier |isbn=978-0-12-383872-8 |language=en}}
+*{{cite book |last1=Mendelson |first1=Avi |title=Handbook of Computer Architecture |date=2022 |editor=Anupam Chattopadhyay |publisher=Springer Nature |isbn=978-981-15-6401-7 |pages=1–42 |chapter-url=https://link.springer.com/referenceworkentry/10.1007/978-981-15-6401-7_1-1 |language=en |chapter=The Architecture|doi=10.1007/978-981-15-6401-7_1-1 }}
+* {{cite book |last1=Wang |first1=Shuangbao Paul |title=Computer Architecture and Organization: Fundamentals and Architecture Security |date=2021 |publisher=Springer Nature |isbn=978-981-16-5662-0 |language=en}}
 ==External links==
+* {{Wikibooks inline}}
 {{Basic computer components}}
 {{Computer science}}
 {{Digital electronics}}
 [[Category:Computer hardware| ]]
 [[Category:Digital electronics]]
 {{Sourceattribution|Computer hardware}}

v t e Basic computer components
Input devices	Keyboard Image scanner Microphone Pointing device Graphics tablet Game controller Light pen Mouse Optical Pointing stick Touchpad Touchscreen Trackball Refreshable braille display Sound card Sound chip Webcam Softcam Video card GPU
Output devices	Monitor Screen Refreshable braille display Printer Plotter Speakers Sound card Video card
Removable data storage	Disk pack Floppy disk Optical disc CD DVD Blu-ray Flash memory Memory card USB flash drive
Computer case	Central processing unit Microprocessor Motherboard Memory RAM BIOS Data storage HDD SSD SSHD Power supply SMPS MOSFET Power MOSFET VRM Network interface controller Fax modem Expansion card
Ports	Ethernet FireWire (IEEE 1394) Parallel port Serial port PS/2 port USB Thunderbolt DisplayPort / HDMI / DVI / VGA eSATA Audio jack

v t e Computer science
Note: This template roughly follows the 2012 ACM Computing Classification System.
Hardware	Printed circuit board Peripheral Integrated circuit Very Large Scale Integration Systems on Chip (SoCs) Energy consumption (Green computing) Electronic design automation Hardware acceleration
Computer systems organization	Computer architecture Embedded system Real-time computing Dependability
Networks	Network architecture Network protocol Network components Network scheduler Network performance evaluation Network service
Software organization	Interpreter Middleware Virtual machine Operating system Software quality
Software notations and tools	Programming paradigm Programming language Compiler Domain-specific language Modeling language Software framework Integrated development environment Software configuration management Software library Software repository
Software development	Software development process Requirements analysis Software design Software construction Software deployment Software maintenance Programming team Open-source model
Theory of computation	Model of computation Formal language Automata theory Computational complexity theory Logic Semantics
Algorithms	Algorithm design Analysis of algorithms Algorithmic efficiency Randomized algorithm Computational geometry
Mathematics of computing	Discrete mathematics Probability Statistics Mathematical software Information theory Mathematical analysis Numerical analysis
Information systems	Database management system Information storage systems Enterprise information system Social information systems Geographic information system Decision support system Process control system Multimedia information system Data mining Digital library Computing platform Digital marketing World Wide Web Information retrieval
Security	Cryptography Formal methods Security services Intrusion detection system Hardware security Network security Information security Application security
Human–computer interaction	Interaction design Social computing Ubiquitous computing Visualization Accessibility
Concurrency	Concurrent computing Parallel computing Distributed computing Multithreading Multiprocessing
Artificial intelligence	Natural language processing Knowledge representation and reasoning Computer vision Automated planning and scheduling Search methodology Control method Philosophy of artificial intelligence Distributed artificial intelligence
Machine learning	Supervised learning Unsupervised learning Reinforcement learning Multi-task learning Cross-validation
Graphics	Animation Rendering Image manipulation Graphics processing unit Mixed reality Virtual reality Image compression Solid modeling
Applied computing	E-commerce Enterprise software Computational mathematics Computational physics Computational chemistry Computational biology Computational social science Computational engineering Computational healthcare Digital art Electronic publishing Cyberwarfare Electronic voting Video games Word processing Operations research Educational technology Document management
Book Category Outline WikiProject Commons

v t e Digital electronics
Components	Combinational logic Sequential logic Integrated circuit (IC) Logic gate
Theory	Digital signal Boolean algebra Logic synthesis Logic in computer science Computer architecture Digital signal Digital signal processing Circuit minimization Switching circuit theory
Design	Logic synthesis Place and route Placement Routing Register-transfer level Hardware description language High-level synthesis Formal equivalence checking Synchronous logic Asynchronous logic Finite-state machine Hierarchical state machine
Applications	Computer hardware Hardware acceleration Digital audio radio Digital photography Digital telephone Digital video cinema television Electronic literature
Design issues	Metastability Runt pulse

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