computer hardware pdp11 cpu board computer hardware includes the physical tangible parts or components of a computer such as the central processing unit monitor keyboard computer data storage graphic card sound card speakers and motherboard by contrast software is instructions that can be stored and run by hardware hardware is sotermed because it is hard or rigid with respect to changes or modifications whereas software is soft because it can be easily updated or changed 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 von neumann architecture von neumann architecture and storedprogram computer 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 types of computer systems personal computer 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 inside a custombuilt 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 lowerpower or reduced size components thus lower performance case 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 extra internal space for multiple disk drives or other peripherals and usually stand on the floor while desktop cases provide less expansion room allinone style designs from apple namely the imac and similar types 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 touchscreen tablet hobbyists may decorate the cases with colored lights paint or other features in an activity called case modding power supply power supply unit a power supply unit psu converts alternating current ac electric power to lowvoltage dc power for the internal components of the computer laptops are capable of running from a builtin battery normally for a period of hours motherboard 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 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 watercooling system most newer cpus include an ondie graphics processing unit gpu the clock speed of cpus governs how fast it executes instructions and is measured in ghz typical values lie between 1ghz and 5ghz 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 randomaccess 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 readonly 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 expansion card 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 expansions cards can be used to obtain or expand on features not offered by the motherboard storage devices computer data storage 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 fixed media 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 solidstate drives are faster and more power efficient although currently more expensive than hard drives in terms of dollar per gigabyte some systems may use a disk array controller for greater performance or reliability removable media 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 peripheral 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 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 device output devices display information in a human readable form such devices could include printers speakers monitors or a braille embosser mainframe computer 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 an ibm system z9 mainframe departmental computing minicomputer 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 supercomputer supercomputer 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 1223 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 1015 or 1000 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 30 expansion card in order to fully use usb 30 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 sales this section needs to be updated please update this article to reflect recent events or newly available information september 2018 for the third consecutive year us businesstobusiness channel sales sales through distributors and commercial resellers increased ending up in 2013 at nearly 6 percent at 617 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 69 percent increase over the fourth quarter of 2012 recycling computer recycling because computer parts contain hazardous materials there is a growing movement to recycle old and outdated parts 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 semiconductors infrared detectors stabilizers cables and wires contain cadmium the circuit boards in a computer contain mercury and chromium 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 ewaste actually is recycled when ewaste 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 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 information technology portal computer architecture electronic hardware glossary of computer hardware terms history of computing hardware list of computer hardware manufacturers opensource computing hardware media related to computer hardware at wikimedia commons learning materials related to computer hardware at wikiversity vtebasic computer componentsinput devices keyboard image scanner microphone pointing device graphics tablet joystick light pen mouse optical pointing stick touchpad touchscreen trackball refreshable braille display sound card webcam softcam video card output devices monitor refreshable braille display printer speakers plotter sound card video card removable data storage optical disc cd dvd bluray disk pack floppy disk memory card usb flash drive computer case central processing unit cpu hdd ssd sshd motherboard network interface controller power supply randomaccess memory ram fax modem expansion card ports ethernet firewire ieee 1394 parallel port serial port ps2 port usb thunderbolt displayport hdmi dvi vga esata audio jack vtemajor fields of computer sciencenote this template roughly follows the 2012 acm computing classification systemhardware printed circuit board peripheral integrated circuit very large scale integration systems on chip socs energy consumption green computing electronic design automation hardware acceleration computer systemsorganization computer architecture embedded system realtime 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 notationsand tools programming paradigm programming language compiler domainspecific 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 opensource 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 mathematicsof computing discrete mathematics probability statistics mathematical software information theory mathematical analysis numerical analysis informationsystems 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 humancomputerinteraction interaction design social computing ubiquitous computing visualization accessibility concurrency concurrent computing parallel computing distributed computing multithreading multiprocessing artificialintelligence 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 multitask learning crossvalidation graphics animation rendering image manipulation graphics processing unit mixed reality virtual reality image compression solid modeling appliedcomputing ecommerce 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 portal wikiproject commons authority control gnd 40234228 