Glossary of computer hardware terms

<a href="/facts/Accelerated_Graphics_Port/kmrNmn8U">Accelerated Graphics Port</a> (AGP)
A dedicated video bus standard introduced by INTEL enabling 3D graphics capabilities; commonly present on an AGP slot on the motherboard. (Presently a historical  <a href="/facts/Expansion_card/QkWAPnxJ">expansion card</a> standard, designed for attaching a video card to a computer's motherboard (and considered high-speed at launch, one of the last off-chip <a href="/facts/Parallel_communication/9quqJd8G">parallel communication</a> standards), primarily to assist in the acceleration of <a href="/facts/3D_computer_graphics/zlWW6eaF">3D computer graphics</a>). Has largely been replaced by PCI Express since the mid 2000s.

<a href="/facts/Hardware_acceleration/ej5sM7hB">accelerator</a>
A microprocessor, ASIC, or expansion card designed to offload a specific task from the CPU, often containing fixed-function hardware. A common example is a graphics processing unit.

<a href="/facts/Accumulator_(computing)/gH4V0l76">accumulator</a>
A register that holds the result of previous operation in ALU. It can be also used as an input register to the adder.

<a href="/facts/Address_(computing)/EscyYKkP">address</a>
The unique <a href="/facts/Integer/PUwwrawx">integer</a> number that identifies a memory location or an input/output port in an address space.

<a href="/facts/Address_space/EscyYKkP">address space</a>
A mapping of logical addresses into <a href="/facts/Physical_memory/wPHKFpdx">physical memory</a> or other memory-mapped devices.

<a href="/facts/ATX/lzxcKxLF">Advanced Technology eXtended</a> (ATX)
A motherboard form factor specification developed by Intel in 1995 to improve on previous DE factor standards like the AT form factor.

<a href="/facts/AI_accelerator/k0QuXHIb">AI accelerator</a>
An accelerator aimed at running <a href="/facts/Artificial_neural_network/6V1jMlkx">artificial neural networks</a> or other <a href="/facts/Machine_learning/e0w0XJTu">machine learning</a> and <a href="/facts/Machine_vision/8kvmXVcA">machine vision</a> algorithms (either training or deployment), e.g. <a href="/facts/Movidius_Myriad_2/zI9kf2U9">Movidius Myriad 2</a>, <a href="/facts/TrueNorth/gcwGPUC7">TrueNorth</a>, <a href="/facts/Tensor_processing_unit/aVlg0LFF">tensor processing unit</a>, etc.

<a href="/facts/Advanced_Configuration_and_Power_Interface/GnLLzfyr">Advanced Configuration and Power Interface</a>
An open standard for operating systems to discover, configure, manage, and monitor status of the hardware.

<a href="/facts/Blu-ray_Disc/zyPalhfG">Blu-ray Disc</a> (BD)
An optical disc storage medium designed to supersede the DVD format. Blu-ray Disc is capable of storing about 5 times as much data as a standard DVD. Most computers do not come shipped with Blu-ray drives, however they can be purchased and added as a separate upgrade. Blu-ray won a <a href="/facts/Format_war/77NuAtYp">format war</a> against <a href="/facts/HD_DVD/ULvpqYxb">HD DVD</a> and for a time drives offering both formats were sold.

<a href="/facts/Bus_(computing)/R45TKwS7">bus</a>
A common path shared by multiple subsystems or components to send / receive signals. It is a low cost option in mini and micro computers compared to multiple dedicated non- shared paths in main frame computers.

<a href="/facts/Bottleneck_(disambiguation)/qNdld1qY">Bottleneck</a>
An occurrence where a certain component compromises the way another component works.

<a href="/facts/Cache_(computing)/gmJYN8wm">cache</a>
A small and fast buffer memory between the CPU and the main memory. Reduces access time for frequently accessed items (instructions / operands).

<a href="/facts/Cache_coherency/MhUD576q">cache coherency</a>
The process of keeping data in multiple caches synchronised in a multiprocessor shared memory system, also required when DMA modifies the underlying memory.

<a href="/facts/Cache_eviction/x8BYFcdv">cache eviction</a>
Freeing up data from within a cache to make room for new cache entries to be allocated; controlled by a <a href="/facts/Cache_replacement_policy/LFW5UqPo">cache replacement policy</a>. Caused by a cache miss whilst a cache is already full.

<a href="/facts/Cache_hit/gmJYN8wm">cache hit</a>
Finding <a href="/facts/Data_(computing)/cPjfFHph">data</a> in a local cache, preventing the need to search for that resource in a more distant location (or to repeat a calculation).

<a href="/facts/CPU_cache/x8BYFcdv">cache line</a>
A small block of memory within a cache; the granularity of allocation, refills, eviction; typically 32–128 bytes in size.

<a href="/facts/Cache_miss/gmJYN8wm">cache miss</a>
Not finding <a href="/facts/Data_(computing)/cPjfFHph">data</a> in a local cache, requiring use of the cache policy to allocate and fill this data, and possibly performing <a href="/facts/Cache_eviction/x8BYFcdv">evicting</a> other data to make room.

<a href="/facts/Cache_thrashing/7Xvz6xEa">cache thrashing</a>
A pathological situation where access in a cache cause cyclical <a href="/facts/Cache_misses/gmJYN8wm">cache misses</a> by <a href="/facts/Cache_eviction/x8BYFcdv">evicting</a> data that is needed in the near future.

cache ways
The number of potential cache lines in an <a href="/facts/Associative_cache/x8BYFcdv">associative cache</a> that specific physical addresses can be mapped to; higher values reduce potential collisions in allocation.

<a href="/facts/Cache-only_memory_architecture/qQea99Gn">cache-only memory architecture</a> (COMA)
A multiprocessor memory architecture where an address space is dynamically shifted between processor nodes based on demand.

<a href="/facts/Card_reader/zql4fN7a">card reader</a>
Any data input device that reads data from a card-shaped storage medium such as a memory card.<a class="footnote-ref" id="fnref:1" href="#fn:1"><sup>1</sup></a><a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a><a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a>

<a href="/facts/Channel_I/O/vDBtN2wQ">channel I/O</a>
A generic term that refers to a high-performance input/output (I/O) architecture that is implemented in various forms on a number of computer architectures, especially on mainframe computers.

<a href="/facts/Chipset/0xU3kbVI">chipset</a>
<p>Also chip set.</p>
A group of integrated circuits, or chips, that are designed to work together. They are usually marketed as a single product.

<a href="/facts/CD-R/yjBjpaIM">Compact Disc-Recordable</a> (CD-R)
A variation of the optical compact disc which can be written to once.

<a href="/facts/CD-RW/W7THUREl">Compact Disc-ReWritable</a> (CD-RW)
A variation of the optical compact disc which can be written to many times.

<a href="/facts/CD-ROM/JwuaYLJv">Compact Disc Read-Only Memory</a> (CD-ROM)
A pre-pressed compact disc which contains data or music playback and which cannot be written to.

<a href="/facts/Computer_case/wG3fchB2">computer case</a>
<p>Also chassis, cabinet, box, tower, enclosure, housing, system unit, or simply case.</p>
The enclosure that contains most of the components of a computer, usually excluding the display, keyboard, mouse, and various other peripherals.

<a href="/facts/Computer_fan/yDmyl4XI">computer fan</a>
An <a href="/facts/Active_cooling/MXEHo6w9">active cooling</a> system forcing <a href="/facts/Airflow/aQY3C0Mw">airflow</a> inside or around a computer case using a <a href="/facts/Fan_(machine)/DL6hHGJJ">fan</a> to cause <a href="/facts/Air_cooling/89q2pkAT">air cooling</a>.

<a href="/facts/Computer_form_factor/2voHRBem">computer form factor</a>
The name used to denote the dimensions, power supply type, location of mounting holes, number of ports on the back panel, etc.

<a href="/facts/Control_store/Ts50verp">control store</a>
The memory that stores the microcode of a CPU.

<a href="/facts/Conventional_PCI/n6CGuFvP">Conventional Peripheral Component Interconnect</a> (Conventional PCI)
<p>Also simply PCI.</p>
A computer bus for attaching hardware devices in a computer.

<a href="/facts/CPU/Jxp1bqMV">core</a>
The portion of the CPU which actually performs <a href="/facts/Arithmetic/hvHwkbMV">arithmetic</a> and <a href="/facts/Logical_operations/VkPhUs6M">logical operations</a>; nearly all CPUs produced since the late 2000s decade have multiple cores (e.g. "a quad-core processor").

<a href="/facts/Core_memory/4TFIXSNd">core memory</a>
In modern usage, a synonym for main memory, dating back from the pre-semiconductor-chip times when the dominant main memory technology was <a href="/facts/Magnetic_core_memory/4TFIXSNd">magnetic core memory</a>.

<a href="/facts/CPU/Jxp1bqMV">Central Processing Unit</a> (CPU)
The portion of a computer system that executes the instructions of a computer program.

<a href="/facts/Data_cache/x8BYFcdv">data cache</a> (D-cache)
A cache in a CPU or GPU servicing data <a href="/facts/Load_and_store/8QEBxzRl">load and store</a> requests, mirroring main memory (or VRAM for a GPU).

<a href="/facts/Computer_data_storage/wPHKFpdx">data storage</a>
A technology consisting of computer components and <a href="/facts/Data_storage_device/uCvJ6nrq">recording media</a> used to retain digital <a href="/facts/Data_(computing)/cPjfFHph">data</a>. It is a core function and fundamental component of computers.<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a>

device memory
local memory associated with a hardware device such as a graphics processing unit or <a href="/facts/OpenCL/ns8y6np7">OpenCL</a> <a href="/facts/Compute_device/ns8y6np7">compute device</a>, distinct from main memory.

<a href="/facts/Digital_Video_Disc/7fJsHJrN">Digital Video Disc</a> (DVD)
<p>Also Digital Versatile Disc.</p>
An optical compact disc - of the same dimensions as compact discs (CDs), but store more than six times as much data. Primarily used for storing <a href="/facts/Film/wM3b9Kk3">movies</a> and computer games, however, the rise of services such as <a href="/facts/Steam_(service)/nrpWwLA9">Steam</a> have largely rendered physical game discs obsolete.

<a href="/facts/Digital_Visual_Interface/Dpnu9JmB">Digital Visual Interface</a> (DVI)
A video display interface developed by the Digital Display Working Group (DDWG). The digital interface is used to connect a video source to a display device, such as a computer monitor.

<a href="/facts/Direct_Access_Storage_Device/dr0tg5Hl">Direct Access Storage Device</a> (DASD)
A mainframe terminology introduced by IBM denoting secondary storage with random access, typically (arrays of) hard disk drives.

<a href="/facts/Direct_mapped_cache/MuBjrreM">direct mapped cache</a>
A cache where each physical address may only be mapped to one cache line, indexed using the low bits of the address. Simple but highly prone to allocation conflicts.

<a href="/facts/Direct_memory_access/DWuVgclV">direct memory access</a> (DMA)
The ability of a <a href="/facts/Hardware_device/8jSjsCNv">hardware device</a> such as a disk drive or <a href="/facts/Network_interface_controller/wyf5FR29">network interface controller</a> to access main memory without intervention from the CPU, provided by one or more <a href="/facts/DMA_channel/DWuVgclV">DMA channels</a> in a system.

<a href="/facts/DisplayPort/rJSvGhBN">DisplayPort</a>
A digital display interface developed by the Video Electronics Standards Association (VESA). The interface is primarily used to connect a video source to a display device such as a computer monitor, though it can also be used to transmit audio, USB, and other forms of data. Unline HDMI, DisplayPort is open source.

<a href="/facts/Drive_bay/kb4WHh3g">drive bay</a>
A standard-sized area within a computer case for adding hardware (hard drives, CD drives, etc.) to a computer.

<a href="/facts/DIMM/Ejh7lpxq">dual in-line memory module</a> (DIMM)
A series of dynamic random-access memory integrated circuits. These modules are mounted on a printed circuit board and designed for use in personal computers, workstations and servers. Contrast <i>SIMM</i>.

dual issue
A <a href="/facts/Superscalar/gPxRAb25">superscalar</a> pipeline capable of executing two instructions simultaneously.

<a href="/facts/Dynamic_random-access_memory/koI9FGo5">dynamic random-access memory</a> (DRAM)
A type of random-access memory that stores each bit of data in a separate capacitor within an integrated circuit and which must be periodically refreshed to retain the stored data.

<a href="/facts/Expansion_bus/QkWAPnxJ">expansion bus</a>
A computer bus which moves information between the internal hardware of a computer system (including the CPU and RAM) and peripheral devices. It is a collection of wires and <a href="/facts/Communications_protocol/5uady7cB">protocols</a> that allows for the expansion of a computer.

<a href="/facts/Expansion_card/QkWAPnxJ">expansion card</a>
A <a href="/facts/Printed_circuit_board/muSR2p43">printed circuit board</a> that can be inserted into an <a href="/facts/Electrical_connector/rJh0cHs6">electrical connector</a> or expansion slot on a computer motherboard, backplane, or riser card to add functionality to a computer system via an expansion bus.

<a href="/facts/Firewall_(computing)/Et2RkJaU">firewall</a>
Any hardware device or software program designed to protect a computer from viruses, trojans, malware, etc.

<a href="/facts/Firmware/62UVKIUK">firmware</a>
Fixed programs and data that internally control various electronic devices.

<a href="/facts/Flash_memory/Cn8JsStx">flash memory</a>
A type of non-volatile computer storage chip that can be electrically erased and reprogrammed.

<a href="/facts/Floppy_disk/rShxfuxa">floppy disk</a>
A data storage medium that is composed of a disk of thin, flexible ("floppy") magnetic storage medium encased in a square or rectangular plastic shell. Historically floppy disks came in 8-inch, 5.25-inch, and 3.5-inch sizes, with the latter being by far the most ubiquitous.

<a href="/facts/Floppy_disk_drive/rShxfuxa">floppy disk drive</a>
A device for reading floppy disks. These were common on computers made prior to 2010.

<a href="/facts/Floppy-disk_controller/re4fpWCW">floppy-disk controller</a>
A specific area on the motherboard which can be used to connect a floppy disk drive to it.

<a href="/facts/Free_and_open-source_graphics_device_driver/h1Wo2nME">free and open-source graphics device driver</a>

<a href="/facts/Graphics_hardware/ngNe2nDc">graphics hardware</a>

<a href="/facts/Graphics_processing_unit/PTK1RQVp">Graphics Processing Unit</a> (GPU)
A specialized processor designed for the purpose of creating images and animations and displaying them on a computer screen, independent of the CPU and onboard video memory.

<a href="/facts/Hard_disk_drive/kekLSGSE">hard disk drive</a> (HDD)
Any non-volatile storage device that stores data on rapidly rotating rigid (i.e. hard) platters with magnetic surfaces.

<a href="/facts/Computer_hardware/8jSjsCNv">hardware</a>
The physical components of a computer system.

<a href="/facts/Harvard_architecture/n9YMly7Q">Harvard architecture</a>
A memory architecture where <a href="/facts/Program_machine_code/bgdQ1Fxf">program machine code</a> and data are held in separate memories, more commonly seen in microcontrollers and <a href="/facts/Digital_signal_processor/YuBXweos">digital signal processors</a>.

<a href="/facts/HDMI/HuNwzm04">High-Definition Multimedia Interface</a> (HDMI)
A compact interface for transferring encrypted uncompressed digital audio and video data to a device such as a computer monitor, video projector or digital television. Motherboard and graphics card manufacturers must pay a licensing fee to incorporate HDMI into their products.

<a href="/facts/Input_device/TXYLUkux">input device</a>
Any peripheral equipment used to provide data and control signals to an information processing system.

<a href="/facts/Input/output/WQTE8Jas">input/output</a> (I/O)
The communication between an information processing system (such as a computer), and the outside world.

<a href="/facts/IOPS/odYyohYu">Input/Output Operations Per Second</a> (IOPS)
A common performance measurement used to benchmark <a href="/facts/Computer_storage_device/wPHKFpdx">computer storage devices</a> like hard disk drives.

<a href="/facts/Instruction_(computer_science)/8p8vwUeE">instruction</a>
A group of several bits in a computer program that contains an operation code and usually one or more memory addresses.

<a href="/facts/Instruction_cache/x8BYFcdv">instruction cache</a>
I-cache
A cache in a CPU or GPU servicing instruction fetch requests for program code (or <a href="/facts/Shader/qfhkKFwA">shaders</a> for a GPU), possibly implementing <a href="/facts/Modified_Harvard_architecture/JhWgY0Ph">modified Harvard architecture</a> if <a href="/facts/Program_machine_code/bgdQ1Fxf">program machine code</a> is stored in the same address space and <a href="/facts/Physical_memory/wPHKFpdx">physical memory</a> as data.

instruction fetch
A stage in a pipeline that loads the next instruction referred to by the program counter.

<a href="/facts/Integrated_circuit/fjn6vg7C">integrated circuit</a>
<p>Also chip.</p>
A miniaturised <a href="/facts/Electronic_circuit/IRfQ6Cc2">electronic circuit</a> that has been manufactured in the surface of a thin substrate of <a href="/facts/Semiconductor/zFf3mGTE">semiconductor</a> material.

<a href="/facts/Interrupt/Mm6C4rpc">interrupt</a>
A condition related to the state of the hardware that may be signaled by an external hardware device.

jump drive
Another name for a USB flash drive.

<a href="/facts/Keyboard_(computing)/MczF9LIS">keyboard</a>
An input device, partially modeled after the <a href="/facts/Typewriter_keyboard/CHE43FWP">typewriter keyboard</a>, which uses an arrangement of buttons or <a href="/facts/Keyboard_(computing)/MczF9LIS">keys</a> to act as mechanical levers or <a href="/facts/Electronic_switch/V6mkIP2z">electronic switches</a>.

<a href="/facts/Instruction_set/8p8vwUeE">load/store instructions</a>
<a href="/facts/Instruction_(computing)/8p8vwUeE">instructions</a> used to transfer data between memory and processor registers.

<a href="/facts/Load%E2%80%93store_architecture/nplXcr1B">load–store architecture</a>
An <a href="/facts/Instruction_set_architecture/8p8vwUeE">instruction set architecture</a> where <a href="/facts/Arithmetic/logic_instruction/8p8vwUeE">arithmetic/logic instructions</a> may only be performed between processor registers, relying on separate load/store instructions for all data transfers.

local memory
memory associated closely with a processing element, e.g. a cache, scratchpad, the memory connected to one processor node in a NUMA or COMA system, or device memory (such as VRAM) in an accelerator.

<a href="/facts/Magneto-optical_drive/PYm8dL1h">magneto-optical drive</a>

<a href="/facts/Mainframe_computer/nrBR6rWa">mainframe computer</a>
An especially powerful computer used mainly by large organizations for bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.

<a href="/facts/Main_memory/wPHKFpdx">main memory</a>
The largest random-access memory in a memory hierarchy (before offline storage) in a computer system. Main memory usually consists of DRAM, and is distinct from caches and scratchpads.

<a href="/facts/Mask_ROM/P9QMuDLH">mask ROM</a>
A type of read-only memory (ROM) whose contents are programmed by the integrated circuit manufacturer.

<a href="/facts/Computer_memory/hQKVQ51J">memory</a>
Devices that are used to store data or programs on a temporary or permanent basis for use in an electronic digital computer.

<a href="/facts/Memory_access_pattern/yKthoAXM">memory access pattern</a>
The pattern with which software or some other system (such as an accelerator or DMA channel) accesses, reads, and writes memory on secondary storage. These patterns have implications for locality of reference, parallelism, and the distribution of workload in shared memory systems.

<a href="/facts/Memory_address/7EsUmbea">memory address</a>
The address of a location in a memory or other address space.

<a href="/facts/Memory_architecture/H4fIYwbT">memory architecture</a>
A memory architecture in a <a href="/facts/Computer_system/SQe1aK05">computer system</a>, e.g. NUMA, uniform memory access, COMA, etc.

<a href="/facts/Memory_card/Rwy2lKS2">memory card</a>
A small electronic data storage device consisting of a flat piece of plastic no larger than a thumbnail that can be inserted into a special socket in a computer or a portable electronic device such as a camera or a cell phone in order to provide instant access to removable memory, typically flash memory.

<a href="/facts/Mini-VGA/BM5yr2Fu">mini-VGA</a>
Small connectors used on some laptops and other systems in place of the standard VGA connector.

<a href="/facts/Microcode/XQEsr2X3">microcode</a>
A layer of hardware-level instructions involved in the implementation of higher level machine code instructions in many computers and other processors.

<a href="/facts/Modem/9H0Xwtq0">modem</a>
A device that enables two distant computer systems to communicate with one another. In the past, modems connected to a phone line, however, since the mid 2000s broadband modems have been the predominant type seen.

<a href="/facts/Modified_Harvard_architecture/JhWgY0Ph">modified Harvard architecture</a>
A variation of Harvard architecture used for most CPUs with separate non-coherent instruction and data caches (assuming that code is immutable), but still mirroring the same main memory address space, and possibly sharing higher levels of the same cache hierarchy.

<a href="/facts/Computer_monitor/NRaTDFHc">monitor</a>
An <a href="/facts/Electronic_visual_display/fA0mUcIQ">electronic visual display</a> for computers. A monitor usually comprises the <a href="/facts/Display_device/yX1Mypk0">display device</a>, circuitry, casing, and power supply. The display device in modern monitors is typically a <a href="/facts/Thin_film_transistor_liquid_crystal_display/4Y8CbuLX">thin film transistor liquid crystal display</a> (TFT-LCD) or a flat panel <a href="/facts/LED_display/IT6VF6vd">LED display</a>, whereas older monitors used a <a href="/facts/Cathode_ray_tube/8NVGx5C7">cathode ray tube</a> (CRT).<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a>

<a href="/facts/Motherboard/GXB10heG">motherboard</a>
The central printed circuit board (PCB) in many modern computers which provides a physical platform for attaching and arranging many of the crucial components of the system, usually while also providing connection space for peripherals.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a>

<a href="/facts/Mouse_(computing)/fJpa1tUE">mouse</a>
A pointing device that functions by detecting two-dimensional motion relative to its supporting surface; motion is usually mapped to a cursor in <a href="/facts/Screen_space/GfIomenN">screen space</a>; typically used to control a <a href="/facts/Graphical_user_interface/wBlQFWDP">graphical user interface</a> on a <a href="/facts/Desktop_computer/edFPINdK">desktop computer</a> or for <a href="/facts/Computer-aided_design/5gSXrmmN">CAD</a>, etc.

<a href="/facts/Computer_network/3w5RM99p">network</a>
A collection of computers and other devices connected by communications channels, e.g. by <a href="/facts/Ethernet/nMfhU8tU">Ethernet</a> or <a href="/facts/Wireless_network/yr4SWTdl">wireless networking</a>.

<a href="/facts/Network_interface_controller/wyf5FR29">network interface controller</a>
<p>Also LAN card or network card.</p>
<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a>

<a href="/facts/Network_on_a_chip/yES3YXp0">network on a chip</a> (NOC)
A computer network on a single <a href="/facts/Semiconductor_chip/fjn6vg7C">semiconductor chip</a>, connecting processing elements, fixed-function hardware, or even memories and caches. Increasingly common in <a href="/facts/System_on_a_chip/1RVvVe6N">system on a chip</a> designs.

<a href="/facts/Non-uniform_memory_access/MpmN5mN0">non-uniform memory access</a> (NUMA)

<a href="/facts/Non-volatile_memory/EN72wMD9">non-volatile memory</a>
memory that can retain the stored data even when not powered, as opposed to volatile memory.

<a href="/facts/Non-volatile_random-access_memory/CIYnqh4E">non-volatile random-access memory</a>
Random-access memory (RAM) that retains its data when power is turned off.

<a href="/facts/Operating_system/8XTuvMh2">operating system</a> 
The set of software that manages computer hardware resources and provides common services for <a href="/facts/Computer_program/e38jH9N9">computer programs</a>, typically loaded by the <a href="/facts/BIOS/AYYPUogS">BIOS</a> on <a href="/facts/Booting/j6N1kRpc">booting</a>.

<a href="/facts/Opcode/UaLMp56C">operation code</a>
Several bits in a <a href="/facts/Computer_program/e38jH9N9">computer program</a> instruction that specify which operation to perform.

<a href="/facts/Optical_disc_drive/IM9ugGbU">optical disc drive</a>
A type of disk drive that uses <a href="/facts/Laser_light/jk6PTvvT">laser light</a> or <a href="/facts/Electromagnetic_wave/Ynx7ujCW">electromagnetic waves</a> near the <a href="/facts/Light_spectrum/24LARvFY">light spectrum</a> as part of the process of reading or writing data to or from <a href="/facts/Optical_disc/vjVDB1GH">optical discs</a>.

<a href="/facts/Pen_drive/Jv0qmTCF">pen drive</a>
Another name for a USB flash drive.

pentest
Another name for a <a href="/facts/Penetration_test/Jd7lFd4z">penetration test</a>.

<a href="/facts/Peripheral/3lEBPE14">peripheral</a>
Any device attached to a computer but not part of it.

<a href="/facts/Peripheral_Component_Interconnect/n6CGuFvP">Peripheral Component Interconnect</a> (PCI)
a local computer bus for attaching hardware devices in a computer and which is part of the PCI Local Bus standard

<a href="/facts/Personal_computer/koaYfNce">personal computer</a> (PC)
Any <a href="/facts/General-purpose_computer/SQe1aK05">general-purpose computer</a> whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end user, with no intervening computer operator.

<a href="/facts/Power_supply/4A8zBRHn">power supply</a>
A unit of the computer that converts mains AC to low-voltage regulated DC for the power of all the computer components.

<a href="/facts/Power_supply_unit_(computer)/3nvssXFG">power supply unit</a> (PSU)
Converts <a href="/facts/Mains_electricity/rjE90Hg0">mains AC</a> to low-voltage regulated <a href="/facts/DC_power/r9MNUx84">DC power</a> for the internal components of a computer. Modern personal computers universally use <a href="/facts/Switched-mode_power_supply/YKcyRBtP">switched-mode power supplies</a>. Some power supplies have a manual switch for selecting input voltage, while others automatically adapt to the mains voltage.

prefetch
The process of pre-loading <a href="/facts/Instruction_(computing)/8p8vwUeE">instructions</a> or data into a cache ahead of time, either under manual control via <a href="/facts/Prefetch_instruction/JRrVplfh">prefetch instructions</a> or automatically by a prefetch unit which may use runtime heuristics to predict the future <a href="/facts/Memory_access_pattern/yKthoAXM">memory access pattern</a>.

prefetching
The pre-loading of instructions or <a href="/facts/Data_(computing)/cPjfFHph">data</a> before either is needed by dedicated <a href="/facts/Cache_control_instruction/JRrVplfh">cache control instructions</a> or predictive hardware, to mitigate <a href="/facts/Latency_(engineering)/6Bjhn30H">latency</a>.

<a href="/facts/Printer_(computing)/PnDF2QuF">printer</a>
A peripheral which produces a text or graphics of documents stored in electronic form, usually on physical print media such as paper or transparencies. The two most common types of printers available are <a href="/facts/Inkjet_printing/YWnIfRmG">inkjet</a>, which uses ink cartridges, and <a href="/facts/Laser_printing/fJ2GrUBj">laser</a>, which uses toner.

process node
Refers to a level of <a href="/facts/Semiconductor/zFf3mGTE">semiconductor</a> <a href="/facts/Semiconductor_device_fabrication/Jd23Mu1z">manufacturing technology</a>, one of several successive <a href="/facts/Transistor/Bmr8zwL0">transistor</a> shrinks.

processing element
An <a href="/facts/Electronic_circuit/IRfQ6Cc2">electronic circuit</a> (either a <a href="/facts/Microprocessor/Fx9CaQht">microprocessor</a> or an internal component of one) that may function autonomously or under external control, performing <a href="/facts/Arithmetic_and_logic_operation/8p8vwUeE">arithmetic and logic operations</a> on <a href="/facts/Data_(computing)/cPjfFHph">data</a>, possibly containing local memory, and possibly connected to other processing elements via a <a href="/facts/Computer_network/3w5RM99p">network</a>, <a href="/facts/Network_on_a_chip/yES3YXp0">network on a chip</a>, or <a href="/facts/Cache_hierarchy/9lGPQ5r6">cache hierarchy</a>.

processor node
A <a href="/facts/Processor_(computing)/z3wPljrI">processor</a> in a multiprocessor system or <a href="/facts/Cluster_(computing)/mT7S1BcX">cluster</a>, connected by dedicated communication channels or a <a href="/facts/Network_(computing)/3w5RM99p">network</a>.

<a href="/facts/Programmable_read-only_memory/amoyxIFx">programmable read-only memory</a> (PROM)
A type of <a href="/facts/Non-volatile_memory/EN72wMD9">non-volatile memory</a> chip that may be programmed after the device is constructed.

<a href="/facts/Programmer_(hardware)/1whv1utW">programmer</a>
Any electronic equipment that arranges written software to configure programmable <a href="/facts/Non-volatile_memory/EN72wMD9">non-volatile</a> <a href="/facts/Integrated_circuit/fjn6vg7C">integrated circuits</a> (called programmable devices) such as  <a href="/facts/EPROM/kXcEca36">EPROMs</a>, <a href="/facts/EEPROM/0yAMFY0I">EEPROMs</a>, <a href="/facts/Flash_Memory/Cn8JsStx">Flashes</a>, <a href="/facts/MultiMediaCard/KGkRkvIY">eMMC</a>, <a href="/facts/Magnetoresistive_random-access_memory/WsgKzopf">MRAM</a>, FRAM, <a href="/facts/Non-volatile_random-access_memory/CIYnqh4E">NV RAM</a>, <a href="/facts/Programmable_Array_Logic/H9S0Fd1A">PALs</a>, <a href="/facts/Field_Programmable_Gate_Array/M8LSGcAU">FPGAs</a> or <a href="/facts/Programmable_logic/7dIVypm9">programmable logic</a> circuits.

<a href="/facts/PCI_Express/ADhsLCUK">PCI Express</a> (PCIe)
An expansion bus standard designed to replace the older PCI, PCI-X, and AGP bus standards.

<a href="/facts/PCI-X/toN6KtKy">PCI-eXtended</a> (PCI-X)
An expansion bus and expansion card standard that enhances the 32-bit PCI Local Bus for higher bandwidth demanded by servers.

<a href="/facts/Redundant_Array_of_Independent_Disks/IpzWWgog">Redundant Array of Independent Disks</a> (RAID)
Any of various data storage schemes that can divide and replicate data across multiple hard disk drives in order to increase reliability, allow faster access, or both.

<a href="/facts/Random-access_memory/DuD4bxh6">random-access memory</a> (RAM)
A type of computer data storage that allows data items to be accessed (<a href="/facts/Read_(computer)/3J8MoCtB">read</a> or written) in almost the same amount of time irrespective of the physical location of data inside the memory. RAM contains <a href="/facts/Multiplexer/lVro0Sfz">multiplexing</a> and <a href="/facts/Demultiplexing/YE7hK8cw">demultiplexing</a> circuitry to connect the data lines to the addressed storage for reading or writing the entry. Usually, more than one bit of storage is accessed by the same address, and RAM devices often have multiple data lines and are said to be '8-bit' or '16-bit' etc. devices. In today's technology, random-access memory takes the form of integrated circuits.

<a href="/facts/Read-only_memory/P9QMuDLH">read-only memory</a> (ROM)
A type of memory chip that retains its data when its power supply is switched off.

<a href="/facts/Server_(computing)/dEaYFD7r">server</a>
A computer which may be used to provide services to clients.

<a href="/facts/Software/RP79lVSW">software</a>
Any <a href="/facts/Computer_program/e38jH9N9">computer program</a> or other kind of information that can be read and/or written by a computer.

<a href="/facts/Single_in-line_memory_module/hSDqXXYb">single in-line memory module</a> (SIMM)
A type of <a href="/facts/Memory_module/sNTAYwr3">memory module</a> containing random-access memory used in computers from the early 1980s to the late 1990s. Contrast <i>DIMM</i>.

<a href="/facts/Solid-state_drive/aMHBy8gU">solid-state drive</a>
<p>Also solid-state disk or electronic disk.</p> 
Any data storage device that uses integrated circuit assemblies as memory to store data persistently. Though they are sometimes referred to as solid-state disks, these devices contain neither an actual disk nor a drive motor to spin a disk. On average, solid-state drives cost about four times as much as conventional hard drives of the same capacity, but can provide significantly faster boot times.

<a href="/facts/Static_random-access_memory/Pmyo4V5e">static random-access memory</a> (SRAM)
A type of <a href="/facts/Semiconductor/zFf3mGTE">semiconductor</a> memory that uses bistable latching circuitry to store each bit. The term static differentiates it from DRAM, which must be periodically refreshed.

<a href="/facts/Sound_card/bxlF4YBa">sound card</a>
<p>Also audio card.</p>
An internal expansion card that facilitates economical input and output of <a href="/facts/Sound/DlKXlPuF">audio signals</a> to and from a computer under control of computer programs.

<a href="/facts/Storage_device_(computing)/wPHKFpdx">storage device</a>

<a href="/facts/Synchronous_dynamic_random-access_memory/regKJe8M">synchronous dynamic random-access memory</a> (SDRAM)
A type of dynamic random access memory that is synchronized with the <a href="/facts/System_bus/p1mxHpbb">system bus</a>.

<a href="/facts/SuperDisk/9KDUgcJG">SuperDisk</a>
A high-speed, high-capacity alternative to the 90 mm (3.5 in), 1.44 <a href="/facts/Megabyte/RBF4XpWb">MB</a> floppy disk. The SuperDisk hardware was created by 3M's storage products group <a href="/facts/Imation/ElJGYYcF">Imation</a> in 1997.

<a href="/facts/Serial_ATA/dW8yAMm8">Serial ATA</a> (SATA)
<p>Also Serial AT Attachment.</p>
A computer bus interface that connects host bus adapters to mass storage devices such as hard disk drives, optical drives, and solid-state drives.

<a href="/facts/Tape_drive/9MfLuCa0">tape drive</a>
A peripheral storage device that allows only <a href="/facts/Sequential_access/8NCL847H">sequential access</a>, typically using <a href="/facts/Magnetic_tape/wj6IDTR1">magnetic tape</a>.
<a href="/facts/Task_manager/SVvCx9Yy">task manager</a>
<a href="/facts/Computer_terminal/fSlx05qV">terminal</a>
An <a href="/facts/Electronic_engineering/WCSVulpu">electronic</a> or <a href="/facts/Electromechanical/0D5gkXko">electromechanical</a> hardware device that is used for entering data into, and displaying data from, a computer or a computing system.

<a href="/facts/Touchpad/5BptytYa">touchpad</a>
<p>Also trackpad.</p>
A pointing device consisting of specialized surface that can translate the motion and position of a user's <a href="/facts/Fingers/v2gDEpbp">fingers</a> or a stylus to a relative position on a screen.<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a>

<a href="/facts/TV_tuner_card/xDY4otBq">TV tuner card</a>
A card that allows the user to view television channels on a computer using an antenna. It can also be used to connect devices such as <a href="/facts/Video_game_console/K72D1NSS">video game consoles</a>, <a href="/facts/Videocassette_recorder/vNXMylt5">videocassette recorders</a>, and <a href="/facts/LaserDisc_player/xHFSR7Pz">LaserDisc players</a>, if necessary.

<a href="/facts/Universal_Serial_Bus/XcIKWLyg">Universal Serial Bus</a> (USB)
A specification to establish communication between devices and a host controller (usually a personal computer). The USB standard was first finalized in 1996, and has undergone many revisions since then, enabling faster data transfer speeds.

<a href="/facts/Uop_cache/x8BYFcdv">uop cache</a>
A cache of decoded <a href="/facts/Micro-operation/9naSl6e9">micro-operations</a> in a <a href="/facts/CISC_processor/Ucvyh2xq">CISC processor</a> (e.g <a href="/facts/X86/Kypq5fgu">x86</a>).<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a>

<a href="/facts/USB_1.x/XcIKWLyg">USB 1.x</a>
The first revision of USB, which was capable of transferring up to 12 Mbit/s (megabits per second).

<a href="/facts/USB_2.0/XcIKWLyg">USB 2.0</a>
The second revision of USB, introduced in 2000. It significantly increased the maximum transfer rate to 480 Mbit/s.

<a href="/facts/USB_3.0/WTnYm1IS">USB 3.0</a>
The third revision of USB, introduced in 2008. It provides transfer rates of up to 5 Gbit/s (gigabits per second), more than 10 times faster than USB 2.0.

<a href="/facts/USB_flash_drive/Jv0qmTCF">USB flash drive</a>
A flash memory device integrated with a USB interface. USB flash drives are typically removable and rewritable.

<a href="/facts/Video_card/bcKfPyFt">video card</a>
<p>Also graphics card.</p>
An expansion card which generates a feed of output images to a display (such as a computer monitor).

<a href="/facts/Video_Graphics_Array/8GGsGTSc">Video Graphics Array</a> (VGA)
First released in 1987, this was the last graphical standard introduced by <a href="/facts/IBM/QszA7nwd">IBM</a> to which the majority of <a href="/facts/PC_clone/zGUpl7Sh">PC clone</a> manufacturers conformed. Today, it has largely been supplanted by DisplayPort and HDMI, however, it can still be found as an integrated graphics option in some motherboards.

<a href="/facts/Volatile_memory/SvvPe9XB">volatile memory</a>
Memory that requires power to maintain the stored information, as opposed to non-volatile memory. Sticks of RAM are an example of volatile memory.

<a href="/facts/Webcam/1vTYrHWw">webcam</a>
A <a href="/facts/Video_camera/pu84VbC7">video camera</a> that feeds its images in real time to a computer or <a href="/facts/Computer_network/3w5RM99p">computer network</a>, often via USB, <a href="/facts/Ethernet/nMfhU8tU">Ethernet</a>, or Wi-Fi.<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a><a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a>

<a href="/facts/Write-back_cache/gmJYN8wm">write-back cache</a>
A cache where store operations are buffered in cache lines, only reaching main memory when the entire cache line is evicted.

<a href="/facts/Write-through_cache/gmJYN8wm">write-through cache</a>
A cache where store operations are immediately written to the underlying main memory.

<a href="/facts/Working_set/z7HKqFa5">working set</a>
The set of data used by a processor during a certain time interval, which should ideally fit into a <a href="/facts/CPU_cache/x8BYFcdv">CPU cache</a> for optimum performance.

<a href="/facts/Zip_drive/m7mUDXTB">zip drive</a>
The Zip drive is a removable floppy disk storage system that was introduced by Iomega in late 1994. Considered medium-to-high-capacity at the time of its release, Zip disks were originally launched with capacities of 100 MB.

<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/List_of_computer_term_etymologies/F71td6cm">List of computer term etymologies</a></li>
<li><a href="/facts/Glossary_of_backup_terms/EHJGhm6X">Glossary of backup terms</a></li>
<li><a href="/facts/Glossary_of_computer_graphics/GfIomenN">Glossary of computer graphics</a></li>
<li><a href="/facts/Glossary_of_computer_science/WEfxGJzI">Glossary of computer science</a></li>
<li><a href="/facts/Glossary_of_computer_software_terms/gg1KaTN0">Glossary of computer software terms</a></li></ul>
<ul><li>Glossary of energy efficient hardware/software</li>
<li><a href="/facts/Glossary_of_Internet-related_terms/Ar1PvP8a">Glossary of Internet-related terms</a></li>
<li><a href="/facts/Glossary_of_reconfigurable_computing/HDAs3Gjm">Glossary of reconfigurable computing</a></li></ul>

<h2 id="external-links">External links</h2>
<ul><li><a href="https://www.jedec.org/standards-documents/dictionary">Dictionary: JESD88 | JEDEC</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>Shelly, G.; Vermaat, M. (2008). Discovering Computers: Fundamentals. Available Titles Skills Assessment Manager (SAM) - Office 2010 Series. Cengage Learning. p. 6. ISBN 978-1-4239-2702-0. Retrieved May 25, 2016. <a href="978-1-4239-2702-0" target="_blank">978-1-4239-2702-0</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>"Punched Card System for a Wholesale Hardware". Volume 7. The Punched Card Machine Accounting and Data Processing Semi-annual. 1952. p. 123. Retrieved 18 May 2016. <a href="https://books.google.com/books?id=dcdPAAAAYAAJ&q=%22hardware%22+Punched+card" target="_blank">https://books.google.com/books?id=dcdPAAAAYAAJ&q=%22hardware%22+Punched+card</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>Kent, Allen; Lancour, Harold (2016-05-11). Encyclopedia of Library and Information Science. CRC Press. p. 277. ISBN 9780824720025. Retrieved 2016-05-25. <a href="9780824720025" target="_blank">9780824720025</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>Shelly, G.; Vermaat, M. (2008). Discovering Computers: Fundamentals. Available Titles Skills Assessment Manager (SAM) - Office 2010 Series. Cengage Learning. p. 6. ISBN 978-1-4239-2702-0. Retrieved May 25, 2016. <a href="978-1-4239-2702-0" target="_blank">978-1-4239-2702-0</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
<li id="fn:5"><p>Shelly, G.; Vermaat, M. (2008). Discovering Computers: Fundamentals. Available Titles Skills Assessment Manager (SAM) - Office 2010 Series. Cengage Learning. p. 6. ISBN 978-1-4239-2702-0. Retrieved May 25, 2016. <a href="978-1-4239-2702-0" target="_blank">978-1-4239-2702-0</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li>
<li id="fn:6"><p>Andrews, Jean (2009-12-29). A+ Guide to Hardware: Managing, Maintaining and Troubleshooting. Cengage Learning. ISBN 978-1435487383. <a href="978-1435487383" target="_blank">978-1435487383</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li>
<li id="fn:7"><p>Andrews, Jean (May 11, 2016). A+ Guide to Hardware. Cengage Learning. p. 403. ISBN 978-1133135128. Retrieved May 19, 2016. <a href="978-1133135128" target="_blank">978-1133135128</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li>
<li id="fn:8"><p>Project, Ubuntu Documentation (May 11, 2016). Ubuntu 11.04 Unity Desktop Guide. Fultus Corporation. ISBN 9781596822580. Retrieved May 19, 2016. <a href="9781596822580" target="_blank">9781596822580</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li>
<li id="fn:9"><p>"micro op cache patent". <a href="https://patents.google.com/patent/US8103831" target="_blank">https://patents.google.com/patent/US8103831</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li>
<li id="fn:10"><p>Shelly, G.; Vermaat, M. (2008). Discovering Computers: Fundamentals. Available Titles Skills Assessment Manager (SAM) - Office 2010 Series. Cengage Learning. p. 6. ISBN 978-1-4239-2702-0. Retrieved May 25, 2016. <a href="978-1-4239-2702-0" target="_blank">978-1-4239-2702-0</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li>
<li id="fn:11"><p>Hannon, John J. (May 11, 2016). Emerging Technologies for Construction Delivery. Transportation Research Board. ISBN 9780309097918. Retrieved May 19, 2016. <a href="9780309097918" target="_blank">9780309097918</a> <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li>
</ol>

Glossary of computer hardware terms open-in-new

Glossary of computer hardware terms