Computer hardware

Computer hardware includes the physical, tangible parts or components of a computer, such as the cabinet, central processing unit, monitor, keyboard, computer data storage, graphics card, sound card, speakers and motherboard.[1] By contrast, software is instructions that can be stored and run by hardware. Hardware is so-termed because it is "hard" or rigid with respect to changes or modifications; whereas software is "soft" because it is easy to update or change. Intermediate between software and hardware is "firmware", which is software that is strongly coupled to the particular hardware of a computer system and thus the most difficult to change but also among the most stable with respect to consistency of interface. The progression from levels of "hardness" to "softness" in computer systems parallels a progression of layers of abstraction in computing.

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 components.

PDP-11 CPU board

Von Neumann architecture

Von Neumann Architecture
Von Neumann architecture scheme

The template for all modern computers is the Von Neumann architecture, detailed in a 1945 paper by Hungarian mathematician John von Neumann. This describes a design architecture for an electronic digital computer with subdivisions of a processing unit consisting of an arithmetic logic unit and processor registers, a control unit containing an instruction register and program counter, a memory to store both data and instructions, external mass storage, and input and output mechanisms.[2] The meaning of the term has evolved to mean a stored-program computer in which an instruction fetch and a data operation cannot occur at the same time because they share a common bus. This is referred to as the Von Neumann bottleneck and often limits the performance of the system.[3]

Types of computer systems

Personal computer

Personal computer, exploded 6
Basic hardware components of a modern personal computer, including a monitor, a motherboard, a CPU, a RAM, two expansion cards, a power supply, an optical disc drive, a hard disk drive, a keyboard and a mouse
Computer from inside 018
Inside a custom-built computer: power supply at the bottom has its own cooling fan

The personal computer, also known as the PC, is one of the most common types of computer due to its versatility and relatively low price. Laptops are generally very similar, although they may use lower-power or reduced size components, thus lower performance.


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 extra internal 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. A current development in laptop computers is a detachable keyboard, which allows the system to be configured as a touch-screen tablet. Hobbyists may decorate the cases with colored lights, paint, or other features, in an activity called case modding.

Power supply

A power supply unit (PSU) converts alternating current (AC) electric power to low-voltage DC power for the internal components of the computer. Laptops are capable of running from a built-in battery, normally for a period of hours.[4]


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.

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

  • The CPU (central processing unit), which performs most of the calculations which enable a computer to function, and is sometimes referred to as the brain of the computer. It is usually cooled by a heatsink and fan, or water-cooling system. Most newer CPUs include an on-die graphics processing unit (GPU). The clock speed of CPUs governs how fast it executes instructions, and is measured in GHz; typical values lie between 1 GHz and 5 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.
  • The 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 northbridge, and supports auxiliary interfaces and buses; and, finally, a Super I/O chip, connected through the southbridge, which supports the slowest and most legacy components like serial ports, hardware monitoring and fan control.
  • 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. RAM usually comes on DIMMs in the sizes 2GB, 4GB, and 8GB, but can be much larger.
  • 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" or "booting up". The BIOS (Basic Input Output System) includes boot firmware and power management firmware. Newer motherboards use Unified Extensible Firmware Interface (UEFI) instead of BIOS.
  • Buses that connect the CPU to various internal components and to expand cards for graphics and sound.
  • The CMOS battery, which powers the memory for date and time in the BIOS chip. This battery is generally a watch battery.
  • The 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.

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.

Storage devices

A storage device is any computing hardware and 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.

Data is stored by a computer using a variety of media. Hard disk drives are found in virtually all older computers, due to their high capacity and low cost, but solid-state drives are faster and more power efficient, although currently more expensive than hard drives in terms of dollar per gigabyte,[5] so are often found in personal computers built post-2007.[6] Some systems may use a disk array controller for greater performance or reliability.

To transfer data between computers, a USB flash drive or optical disc may be used. Their usefulness depends on being readable by other systems; the majority of machines have an optical disk drive, and virtually all have at least one USB port.

Input and output peripherals

Input and output devices are typically housed externally to the main computer chassis. The following are either standard or very common to many computer systems.

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 instead of a mouse. Other input devices include webcams, microphones, joysticks, and image scanners.

Output devices display information in a human readable form. Such devices could include printers, speakers, monitors or a Braille embosser.

Mainframe computer

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.

Front Z9 2094
An IBM System z9 mainframe

Departmental computing

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 supercomputer is superficially similar to a mainframe, but is instead intended for extremely demanding computational tasks. As of June 2018, the fastest supercomputer on the TOP500supercomputer list is the Summit, in the United States, with a LINPACK benchmarkscore of 122.3 PFLOPS, exceeding the previous record holder, Sunway TaihuLight, by around 29 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 means adding new hardware to a computer that improves its performance, adds capacity or new features. For example, a user could perform a hardware upgrade to replace the hard drive with a SSD to get a boost in performance or increase the amount of files that may be stored. Also, the user could increase the RAM so the computer may run more smoothly. The user could add a USB 3.0 expansion card in order to fully use USB 3.0 devices, or could upgrade the GPU for extra rendering power. Performing such hardware upgrades may be necessary for older computers to meet a programs' system requirements.


For the third consecutive year, U.S. business-to-business channel sales (sales through distributors and commercial resellers) increased, ending up in 2013 at nearly 6 percent at $61.7 billion. The growth was the fastest sales increase since the end of the recession. Sales growth accelerated in the second half of the year peaking in fourth quarter with a 6.9 percent increase over the fourth quarter of 2012.[7]



Because computer parts contain hazardous materials, there is a growing movement to recycle old and outdated parts.[8] 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 environment unless they are disposed of properly. Making hardware requires energy, and recycling parts will reduce air pollution, water pollution, as well as greenhouse gas emissions.[9] Disposing unauthorized computer equipment is in fact illegal. Legislation makes it mandatory to recycle computers through the government approved facilities. Recycling a computer can be made easier by taking out certain reusable parts. For example, the RAM, DVD drive, the graphics card, hard drive or SSD, and other similar removable parts can be reused.

Toxic computer components

The central processing unit contains many toxic materials. It contains lead and chromium in the metal plates. Resistors, semi-conductors, infrared detectors, stabilizers, cables, and wires contain cadmium. The circuit boards in a computer contain mercury, and chromium.[10] When these types of materials, and chemicals are disposed improperly will become hazardous for 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 ground water, 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.[11] That's 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 is done there are two different piles left; one containing the copper powder, and the other containing plastic/rubber pieces.[12] Computer monitors, mice, and 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.[13]

National services

Recycling a computer is made easier by a few of the national services, such as Dell and Apple. Both companies will take back the computer 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.[14]

See also


  1. ^ "Parts of computer". Microsoft. Archived from the original on 27 November 2013. Retrieved 5 December 2013.
  2. ^ von Neumann, John (1945). "First Draft of a Report on the EDVAC" (PDF). Archived (PDF) from the original on 9 August 2013.
  3. ^ Markgraf, Joey D. (2007). "The Von Neumann bottleneck". Archived from the original on 9 June 2011. Retrieved 24 August 2011.
  4. ^ "How long should a laptop battery last?". Computer Hope. Archived from the original on 21 December 2013. Retrieved 9 December 2013.
  5. ^ Domingo, Joel. "SSD vs. HDD: What's the Difference?". PCMag. Archived from the original on 19 March 2017. Retrieved 24 March 2017.
  6. ^ Edwards, Benj (17 January 2012). "Evolution of the Solid-State Drive". PCWorld. Archived from the original on 25 March 2017. Retrieved 24 March 2017.
  7. ^ "US B2B Channel sales reach nearly $62 Billion in 2013, According to The NPD Group". NPD Group. 4 February 2014. Archived from the original on 8 August 2014.
  8. ^ "How to recycle your old computer". Digital Trends. 18 December 2016. Archived from the original on 17 April 2017. Retrieved 18 April 2017.
  9. ^ Inc, Chris Keenan - Newtech Recycling. "Newtech Recycling Specializes in Computer Disposal, Laptop Disposal, Desktop Disposal Mainframe Disposal and Server Disposal". Archived from the original on 29 March 2017. Retrieved 18 April 2017.
  10. ^ "The Toxic Components of Computers and Monitors". Archived from the original on 27 April 2017. Retrieved 26 April 2017.
  11. ^ "What's Going On with Electronic Waste? – Electronics TakeBack Coalition". Archived from the original on 27 April 2017. Retrieved 26 April 2017.
  12. ^ "Wire Recycling". Archived from the original on 10 July 2017. Retrieved 5 May 2017.
  13. ^ "Computer equipment recycling – Essential Guide". ComputerWeekly. Archived from the original on 21 December 2016. Retrieved 8 May 2017.
  14. ^ Schofield, Jack (19 February 2015). "How can I safely recycle my old PCs?". The Guardian. ISSN 0261-3077. Archived from the original on 27 April 2017. Retrieved 26 April 2017.

External links

Apple 410 Color Plotter

The Apple 410 Color Plotter (OEM Yokogawa's YEW PL-1000) is a color plotter printer that was sold by Apple Computer, Inc. from 1983 to 1988. The colors came in either water- or oil-based inks.

The printer could be connected to an Apple II (with an installed Super Serial Card) or Apple III computer.

Apple Macintosh Color Display

The Apple Macintosh Color Display is a 14" (13" viewable) Trinitron aperture grille CRT that was manufactured by Apple Inc. from October 19, 1992, until at least September 1993. The video cable uses a standard Macintosh DA-15 video connector and the fixed resolution is 640x480.

Apple Multiple Scan 14 Display

The Apple Multiple Scan 14 Display is a 12.4" viewable shadow mask CRT that was manufactured by Apple Inc. from August 7, 1995 until September 14, 1996. This monitor has built-in speakers that can be connected with a cable that has a male miniature TRS connector on each end and there is also a headphone jack. The video cable uses a standard Macintosh DA-15 video connector and the maximum resolution is 800x600.

ColorMonitor IIe/AppleColor Composite Monitor IIe

The ColorMonitor IIe, later renamed AppleColor Composite Monitor IIe is a CRT-based color or gray monochrome (selectable) 13-inch monitor manufactured by Apple Computer for the Apple II personal computer family. This monitor is designed to fit into the grooves on the top of the Apple II, II+, and IIe computers. This monitor has no swiveling option.

Computer engineering

Computer engineering is a branch of engineering that integrates several fields of computer science and electronic engineering required to develop computer hardware and software. Computer engineers usually have training in electronic engineering (or electrical engineering), software design, and hardware-software integration instead of only software engineering or electronic engineering. Computer engineers are involved in many hardware and software aspects of computing, from the design of individual microcontrollers, microprocessors, personal computers, and supercomputers, to circuit design. This field of engineering not only focuses on how computer systems themselves work but also how they integrate into the larger picture.Usual tasks involving computer engineers include writing software and firmware for embedded microcontrollers, designing VLSI chips, designing analog sensors, designing mixed signal circuit boards, and designing operating systems. Computer engineers are also suited for robotics research, which relies heavily on using digital systems to control and monitor electrical systems like motors, communications, and sensors.

In many institutions of higher learning, computer engineering students are allowed to choose areas of in-depth study in their junior and senior year because the full breadth of knowledge used in the design and application of computers is beyond the scope of an undergraduate degree. Other institutions may require engineering students to complete one or two years of general engineering before declaring computer engineering as their primary focus.

Computer industry

The computer or information technology, or IT industry is the range of businesses involved in designing computer hardware and computer networking infrastructures, developing computer software, manufacturing computer components, and providing information technology (IT) services.

Computing platform

A computing platform or digital platform is the environment in which a piece of software is executed. It may be the hardware or the operating system (OS), even a web browser and associated application programming interfaces, or other underlying software, as long as the program code is executed with it. Computing platforms have different abstraction levels, including a computer architecture, an OS, or runtime libraries. A computing platform is the stage on which computer programs can run.

A platform can be seen both as a constraint on the software development process, in that different platforms provide different functionality and restrictions; and as an assistance to the development process, in that they provide low-level functionality ready-made. For example, an OS may be a platform that abstracts the underlying differences in hardware and provides a generic command for saving files or accessing the network.

Gateway, Inc.

Gateway Inc., previously Gateway 2000, was an American computer hardware company based in South Dakota and later California, that developed, manufactured, supported, and marketed a wide range of personal computers, computer monitors, servers, and computer accessories.

It was acquired by Acer in October 2007.

List of companies of Taiwan

Taiwan is a country in East Asia. Neighbors include the People's Republic of China (PRC) to the west, Japan to the northeast, and the Philippines to the south. Taiwan is the most populous non-UN state and the largest economy outside the UN.

Taiwan maintains a stable industrial economy as a result of rapid economic growth and industrialization, which has been dubbed the Taiwan Miracle. Taiwan is one of the Four Asian Tigers and a member of both the World Trade Organization and the Asia-Pacific Economic Cooperation. The 21st-largest economy in the world, its high-tech industry plays a key role in the global economy. Taiwan is ranked highly in terms of freedom of the press, health care, public education, economic freedom, and human development.

Magic Trackpad 2

The Magic Trackpad 2 is a multi-touch and Force Touch trackpad produced by Apple Inc. Announced on October 13, 2015, it is the successor to the Magic Trackpad.

Microsoft hardware

Microsoft hardware has been developed since 1982, when the Microsoft Hardware division was formed to design a computer mouse for use with Microsoft Word for DOS. Since then, Microsoft has developed computer hardware, gaming hardware and mobile hardware. It also produced drivers and other software for integrating the hardware with Microsoft Windows.

Processor (computing)

In computing, a processor or processing unit is an electronic circuit which performs operations on some external data source, usually memory or some other data stream. The term is frequently used to refer to the central processor (central processing unit) in a system, but typical computer systems (especially SoCs) combine a number of specialised "processors".

Removable media

In computer storage, some types of removable media are designed to be read to or written to by removable readers, writers and drives.

Examples include:

Optical discs (Blu-ray discs, DVDs, CDs)

Memory cards (CompactFlash card, Secure Digital card, Memory Stick)

Zip disks/other Floppy disks

Disk packs

Magnetic tapes

Paper data storage (punched cards, punched tapes)Some removable media readers and drives are integrated into computers, others are themselves removable.

Removable media may also refer to some removable storage devices, when they are used to transport or store data. Examples include:

USB flash drives

External hard disk drives; traditional IDE, EIDE, SCSSI, and SSD, for example

Devices that are common today may include

Digital cameras

Smart phones

Wired or Wireless printers

other external/dockable peripheral that can easily be removed from a system, which also contain removable media capabilities


In computing, SISD (single instruction stream, single data stream) is a computer architecture in which a single uni-core processor, executes a single instruction stream, to operate on data stored in a single memory. This corresponds to the von Neumann architecture.

SISD is one of the four main classifications as defined in Flynn's taxonomy. In this system, classifications are based upon the number of concurrent instructions and data streams present in the computer architecture. According to Michael J. Flynn, SISD can have concurrent processing characteristics. Pipelined processors and superscalar processors are common examples found in most modern SISD computers.Instructions are sent to the control unit from the Memory Module and are decoded and sent to the processing unit which processes on the data retrieved from Memory module and sents back to it.

Scalar processor

Scalar processors represent a class of computer processors. A scalar processor processes only one data item at a time, with typical data items being integers or floating point numbers. A scalar processor is classified as a SISD processor (Single Instructions, Single Data) in Flynn's taxonomy.

Tiger Lake (microarchitecture)

Tiger Lake is an Intel CPU microarchitecture based on the second-generation 10nm process node (named "10nm+"). It will replace Ice Lake.Tiger Lake is slated to include quad-core 9 W TDP and 25 W TDP models. It will power some 2020 "Project Athena" laptops.

Ultra Port Architecture

The Ultra Port Architecture (UPA) bus was developed by Sun Microsystems as a high-speed graphics card to CPU interconnect, beginning with the Ultra 1 workstation in 1995.


Xiaomi Corporation (; Chinese: 小米 [ɕjǎu.mì] (listen)) is a Chinese electronics company headquartered in Beijing. Xiaomi makes and invests in smartphones, mobile apps, laptops, and related consumer electronics.Xiaomi released its first smartphone in August 2011 and rapidly gained market share in China to become the country's largest smartphone company in 2014. At the start of second quarter of 2018, Xiaomi was the world's fourth-largest smartphone manufacturer, leading in both the largest market, China, and the second-largest market, India. Xiaomi later developed a wider range of consumer electronics, including a smart home (IoT) device ecosystem.Xiaomi has 15,000 employees in China, India, Malaysia, Singapore and is expanding to other countries including Indonesia, the Philippines, and South Africa. According to Forbes magazine, Lei Jun, the founder and CEO, has an estimated net worth of US$12.5 billion. He is China's 11th richest person and 118th in the world. Xiaomi is the world's 4th most valuable technology start-up after receiving US$1.1 billion funding from investors, making Xiaomi's valuation more than US$46 billion.

Basic computer components
Input devices
Output devices
data storage
Computer case
Computer systems
Software organization
Software notations
and tools
Software development
Theory of computation
of computing
Machine learning

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