Network via one of:
75-502: A network interface controller ( NIC , also known as a network interface card , network adapter , LAN adapter and physical network interface ) is a computer hardware component that connects a computer to a computer network . Early network interface controllers were commonly implemented on expansion cards that plugged into a computer bus . The low cost and ubiquity of the Ethernet standard means that most newer computers have
150-457: A ) = Cons ( x , rotate ( f , r , CONS ( y , a ) ) ) {\displaystyle \operatorname {rotate} (\operatorname {CONS} (x,f),\operatorname {CONS} (y,r),a)=\operatorname {Cons} (x,\operatorname {rotate} (f,r,\operatorname {CONS} (y,a)))} . Its running time is O ( r ) {\displaystyle O(r)} , but, since lazy evaluation
225-432: A monitor , mouse , keyboard , and speakers . By contrast, software is a set of written instructions that can be stored and run by hardware. Hardware derived its name from the fact 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
300-400: A purely functional data structure . There are two implementations. The first one only achieves O ( 1 ) {\displaystyle O(1)} per operation on average . That is, the amortized time is O ( 1 ) {\displaystyle O(1)} , but individual operations can take O ( n ) {\displaystyle O(n)} where n is
375-458: A GPU integrated into the motherboard. Most computers also have an external data bus to connect peripheral devices to the motherboard. Most commonly, Universal Serial Bus (USB) is used. 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. Input and output devices are used to receive data from
450-485: 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
525-590: A commensurate increase in energy use and cooling demand. The personal computer is one of the most common types of computer due to its versatility and relatively low price. 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). 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
600-581: A computer bus. The low cost and ubiquity of the Ethernet standard means that most new computers have a network interface controller built into the motherboard. Newer server motherboards may have multiple network interfaces built-in. The Ethernet capabilities are either integrated into the motherboard chipset or implemented via a low-cost dedicated Ethernet chip. A separate network card is typically no longer required unless additional independent network connections are needed or some non-Ethernet type of network
675-425: A computer network, either by using cables or wirelessly. The NIC is both a physical layer and data link layer device, as it provides physical access to a networking medium and, for IEEE 802 and similar networks, provides a low-level addressing system through the use of MAC addresses that are uniquely assigned to network interfaces. Network controllers were originally implemented as expansion cards that plugged into
750-575: A constant cost for each element in the reverse to when it was inserted. The real-time queue achieves O ( 1 ) {\displaystyle O(1)} time for all operations, without amortization. This discussion will be technical, so recall that, for l {\displaystyle l} a list, | l | {\displaystyle |l|} denotes its length, that NIL represents an empty list and CONS ( h , t ) {\displaystyle \operatorname {CONS} (h,t)} represents
825-399: A cord, light or takes some kind of battery. Some companies, such as Dell and 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. Queue (abstract data type) In computer science , a queue
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#1732790788376900-669: A list (or, in reverse, one can use unshift and pop ), although in some cases these operations are not efficient. C++'s Standard Template Library provides a " queue " templated class which is restricted to only push/pop operations. Since J2SE5.0, Java's library contains a Queue interface that specifies queue operations; implementing classes include LinkedList and (since J2SE 1.6) ArrayDeque . PHP has an SplQueue class and third party libraries like beanstalk'd and Gearman . [REDACTED] A simple queue implemented in JavaScript : Queues can also be implemented as
975-486: A network interface built into the motherboard , or is contained into a USB -connected dongle . Modern network interface controllers offer advanced features such as interrupt and DMA interfaces to the host processors, support for multiple receive and transmit queues, partitioning into multiple logical interfaces, and on-controller network traffic processing such as the TCP offload engine . The network controller implements
1050-415: A queue is that it does not have a specific capacity. Regardless of how many elements are already contained, a new element can always be added. It can also be empty, at which point removing an element will be impossible until a new element has been added again. Fixed-length arrays are limited in capacity, but it is not true that items need to be copied towards the head of the queue. The simple trick of turning
1125-399: A queue make it a first-in-first-out (FIFO) data structure . In a FIFO data structure, the first element added to the queue will be the first one to be removed. This is equivalent to the requirement that once a new element is added, all elements that were added before have to be removed before the new element can be removed. A queue is an example of a linear data structure , or more abstractly
1200-483: A sequential collection. Queues are common in computer programs, where they are implemented as data structures coupled with access routines, as an abstract data structure or in object-oriented languages as classes. A queue has two ends, the top, which is the only position at which the push operation may occur, and the bottom, which is the only position at which the pop operation may occur. A queue may be implemented as circular buffers and linked lists , or by using both
1275-408: A standard receptacle for media-dependent transceivers, so users can easily adapt the network interface to their needs. LEDs adjacent to or integrated into the network connector inform the user of whether the network is connected, and when data activity occurs. The NIC may include ROM to store its factory-assigned MAC address . The NIC may use one or more of the following techniques to indicate
1350-421: A usable computing system, although other systems exist with only hardware. Early computing devices were more complicated than the ancient abacus date to the seventeenth century. French mathematician Blaise Pascal designed a gear-based device that could add and subtract, selling around 50 models. The stepped reckoner was invented by Gottfried Leibniz by 1676, which could also divide and multiply. Due to
1425-400: 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 copper , gold , tantalum , silver , platinum , palladium , and lead as well as other valuable materials suitable for reclamation. The central processing unit contains many toxic materials. It contains lead and chromium in
1500-444: A very similar commodity . Profit margins have also been reduced. 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. 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. Despite
1575-514: Is | s | = | f | − | r | {\displaystyle |s|=|f|-|r|} . The tail of the queue ( CONS ( x , f ) , r , s ) {\displaystyle (\operatorname {CONS} (x,f),r,s)} is then almost ( f , r , s ) {\displaystyle (f,r,s)} and inserting an element x to ( f , r , s ) {\displaystyle (f,r,s)}
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#17327907883761650-450: Is rotate ( NIL , Cons ( y , NIL ) , a ) = Cons ( y , a ) {\displaystyle \operatorname {rotate} ({\text{NIL}},\operatorname {Cons} (y,{\text{NIL}}),a)=\operatorname {Cons} (y,a)} and rotate ( CONS ( x , f ) , CONS ( y , r ) ,
1725-403: Is f followed by r reversed. Let us call reverse ( f , r ) {\displaystyle \operatorname {reverse} (f,r)} the function which returns f followed by r reversed. Let us furthermore assume that | r | = | f | + 1 {\displaystyle |r|=|f|+1} , since it is the case when this function
1800-416: Is a collection of entities that are maintained in a sequence and can be modified by the addition of entities at one end of the sequence and the removal of entities from the other end of the sequence. By convention, the end of the sequence at which elements are added is called the back, tail, or rear of the queue, and the end at which elements are removed is called the head or front of the queue, analogously to
1875-495: Is a growing movement to recycle old and outdated parts. 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. Disposing unauthorized computer equipment
1950-427: Is a particular concern with these systems, with designers often choosing the cheapest option that satisfies the performance requirements. 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
2025-569: Is a queue limited to a fixed number of items. There are several efficient implementations of FIFO queues. An efficient implementation is one that can perform the operations—en-queuing and de-queuing—in O(1) time . Queues may be implemented as a separate data type, or maybe considered a special case of a double-ended queue (deque) and not implemented separately. For example, Perl and Ruby allow pushing and popping an array from both ends, so one can use push and shift functions to enqueue and dequeue
2100-466: Is almost ( f , CONS ( x , r ) , s ) {\displaystyle (f,\operatorname {CONS} (x,r),s)} . It is said almost, because in both of those results, | s | = | f | − | r | + 1 {\displaystyle |s|=|f|-|r|+1} . An auxiliary function a u x {\displaystyle aux} must then be called for
2175-464: 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
2250-669: Is called. More precisely, we define a lazy function rotate ( f , r , a ) {\displaystyle \operatorname {rotate} (f,r,a)} which takes as input three lists such that | r | = | f | + 1 {\displaystyle |r|=|f|+1} , and return the concatenation of f , of r reversed and of a . Then reverse ( f , r ) = rotate ( f , r , NIL ) {\displaystyle \operatorname {reverse} (f,r)=\operatorname {rotate} (f,r,{\text{NIL}})} . The inductive definition of rotate
2325-484: 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. In 1945, Turing finished the design for a computer (the Automatic Computing Engine ) that was never built. Around this time, technological advancement in relays and vacuum tubes enabled the construction of
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2400-527: 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. Many materials used in computer hardware can be recovered by recycling for use in future production. Reuse of tin , silicon , iron , aluminum , and
2475-434: 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. Most computers are designed to be more powerful than their cooling system, but their sustained operations cannot exceed the capacity of the cooling system. While performance can be temporarily increased when the computer is not hot ( overclocking ), in order to protect
2550-402: Is the empty list. This counter allows us to ensure that the rear is never longer than the front list. Furthermore, using s , which is a tail of f , forces the computation of a part of the (lazy) list f during each tail and insert operation. Therefore, when | f | = | r | {\displaystyle |f|=|r|} , the list f is totally forced. If it
2625-537: 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). Components directly attached to or to part of
2700-404: Is used, the computation is delayed until the results are forced by the computation. The list s in the data structure has two purposes. This list serves as a counter for | f | − | r | {\displaystyle |f|-|r|} , indeed, | f | = | r | {\displaystyle |f|=|r|} if and only if s
2775-845: Is used. A general trend in computer hardware is towards integrating the various components of systems on a chip , and this is also applied to network interface cards. An Ethernet network controller typically has an 8P8C socket where the network cable is connected. Older NICs also supplied BNC , or AUI connections. Ethernet network controllers typically support 10 Mbit/s Ethernet, 100 Mbit/s Ethernet , and 1000 Mbit/s Ethernet varieties. Such controllers are designated as 10/100/1000 , meaning that they can support data rates of 10, 100 or 1000 Mbit/s. 10 Gigabit Ethernet NICs are also available, and, as of November 2014, are beginning to be available on computer motherboards . Modular designs like SFP and SFP+ are highly popular, especially for fiber-optic communication . These define
2850-446: Is usually referred to as transmit packet steering (XPS). Some products feature NIC partitioning ( NPAR , also known as port partitioning ) that uses SR-IOV virtualization to divide a single 10 Gigabit Ethernet NIC into multiple discrete virtual NICs with dedicated bandwidth, which are presented to the firmware and operating system as separate PCI device functions . Some NICs provide a TCP offload engine to offload processing of
2925-401: The operating system to map virtual memory to different areas of the finite physical memory. 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
3000-498: The operating system kernel ; Solarflare's open-source OpenOnload network stack that runs on Linux is an example. This kind of functionality is usually referred to as user-level networking . Computer hardware 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
3075-418: The stack pointer and the base pointer. Queues provide services in computer science , transport , and operations research where various entities such as data, objects, persons, or events are stored and held to be processed later. In these contexts, the queue performs the function of a buffer . Another usage of queues is in the implementation of breadth-first search . Theoretically, one characteristic of
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3150-403: 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. 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
3225-548: The annual rate of improvement in hardware performance exceeded 50 percent, enabling the development of new computing devices such as tablets and mobiles. 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. In the twenty-first century, increases in performance have been driven by increasing exploitation of parallelism . Applications are often parallelizable in two ways: either
3300-413: The array indices must be compared to zero and the array size, which is comparable to the time taken to check whether an array index is out of bounds, which some languages do, but this will certainly be the method of choice for a quick and dirty implementation, or for any high-level language that does not have pointer syntax. The array size must be declared ahead of time, but some implementations simply double
3375-410: The array into a closed circle and letting the head and tail drift around endlessly in that circle makes it unnecessary to ever move items stored in the array. If n is the size of the array, then computing indices modulo n will turn the array into a circle. This is still the conceptually simplest way to construct a queue in a high-level language , but it does admittedly slow things down a little, because
3450-650: 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. E-cycling ,
3525-555: The availability of packets to transfer: NICs may use one or more of the following techniques to transfer packet data: Multiqueue NICs provide multiple transmit and receive queues , allowing packets received by the NIC to be assigned to one of its receive queues. The NIC may distribute incoming traffic between the receive queues using a hash function . Each receive queue is assigned to a separate interrupt ; by routing each of those interrupts to different CPUs or CPU cores , processing of
3600-423: The declared array size when overflow occurs. Most modern languages with objects or pointers can implement or come with libraries for dynamic lists. Such data structures may have not specified a fixed capacity limit besides memory constraints. Queue overflow results from trying to add an element onto a full queue and queue underflow happens when trying to remove an element from an empty queue. A bounded queue
3675-443: The design of the CPU, memory, and memory interconnect . 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. Memory is typically segregated to separate programs from data and limit an attacker's ability to alter programs. Most computers use virtual memory to simplify addressing for programs, using
3750-440: 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 . In 1936, Alan Turing developed the universal Turing machine to model any type of computer, proving that no computer would be able to solve the decision problem . The universal Turing machine
3825-428: The electronic circuitry required to communicate using a specific physical layer and data link layer standard such as Ethernet or Wi-Fi . This provides a base for a full network protocol stack , allowing communication among computers on the same local area network (LAN) and large-scale network communications through routable protocols, such as Internet Protocol (IP). The NIC allows computers to communicate over
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#17327907883763900-662: The entire TCP/IP stack to the network controller. It is primarily used with high-speed network interfaces, such as Gigabit Ethernet and 10 Gigabit Ethernet, for which the processing overhead of the network stack becomes significant. Some NICs offer integrated field-programmable gate arrays (FPGAs) for user-programmable processing of network traffic before it reaches the host computer, allowing for significantly reduced latencies in time-sensitive workloads. Moreover, some NICs offer complete low-latency TCP/IP stacks running on integrated FPGAs in combination with userspace libraries that intercept networking operations usually performed by
3975-631: 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 . 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. Global revenue from computer hardware in 2023 reached $ 705.17 billion. Because computer parts contain hazardous materials, there
4050-608: The first computers. 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 . 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. Von Neumann's design featured
4125-400: The front part of the queue. The list r {\displaystyle r} holds the remaining elements (a.k.a., the rear of the queue) in reverse order . It is easy to insert into the front of the queue by adding a node at the head of f {\displaystyle f} . And, if r {\displaystyle r} is not empty, it is easy to remove from the end of
4200-461: The hardware from excessive heat, the system will automatically reduce performance or shut down the processor if necessary. Processors also will shut off or enter a low power mode when inactive to reduce heat. Power delivery as well as heat dissipation are the most challenging aspects of hardware design, and have been the limiting factor to the development of smaller and faster chips since the early twenty-first century. Increases in performance require
4275-719: The interrupt requests to the CPUs or cores executing the applications that are the ultimate destinations for network packets that generated the interrupts. This technique improves locality of reference and results in higher overall performance, reduced latency and better hardware utilization because of the higher utilization of CPU caches and fewer required context switches . With multi-queue NICs, additional performance improvements can be achieved by distributing outgoing traffic among different transmit queues. By assigning different transmit queues to different CPUs or CPU cores, internal operating system contentions can be avoided. This approach
4350-449: The interrupt requests triggered by the network traffic received by a single NIC can be distributed improving performance. The hardware-based distribution of the interrupts, described above, is referred to as receive-side scaling (RSS). Purely software implementations also exist, such as the receive packet steering (RPS), receive flow steering (RFS), and Intel Flow Director . Further performance improvements can be achieved by routing
4425-852: The invariant to be satisfied. Two cases must be considered, depending on whether s {\displaystyle s} is the empty list, in which case | r | = | f | + 1 {\displaystyle |r|=|f|+1} , or not. The formal definition is aux ( f , r , Cons ( _ , s ) ) = ( f , r , s ) {\displaystyle \operatorname {aux} (f,r,\operatorname {Cons} (\_,s))=(f,r,s)} and aux ( f , r , NIL ) = ( f ′ , NIL , f ′ ) {\displaystyle \operatorname {aux} (f,r,{\text{NIL}})=(f',{\text{NIL}},f')} where f ′ {\displaystyle f'}
4500-413: 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. In the 19th century, Englishman Charles Babbage invented the difference engine , a mechanical device to calculate polynomials for astronomical purposes. Babbage also designed a general-purpose computer that was never built. Much of
4575-553: The list r {\displaystyle r} is not empty. When r {\displaystyle r} is empty, the reverse takes O ( n ) {\displaystyle O(n)} where n {\displaystyle n} is the number of elements in f {\displaystyle f} . But, we can say it is O ( 1 ) {\displaystyle O(1)} amortized time, because every element in f {\displaystyle f} had to be inserted and we can assign
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#17327907883764650-469: The list whose head is h and whose tail is t . The data structure used to implement our queues consists of three singly-linked lists ( f , r , s ) {\displaystyle (f,r,s)} where f is the front of the queue and r is the rear of the queue in reverse order. The invariant of the structure is that s is the rear of f without its | r | {\displaystyle |r|} first elements, that
4725-525: The lungs, liver, and kidneys. 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. Recycling of computer hardware is considered environmentally friendly because it prevents hazardous waste , including heavy metals and carcinogens, from entering
4800-506: 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. 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
4875-443: The motherboard include: 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. Using expansion cards for a video processor used to be common, but modern computers are more likely to instead have
4950-534: The number of elements in the queue. The second implementation is called a real-time queue and it allows the queue to be persistent with operations in O(1) worst-case time. It is a more complex implementation and requires lazy lists with memoization . This queue's data is stored in two singly-linked lists named f {\displaystyle f} and r {\displaystyle r} . The list f {\displaystyle f} holds
5025-509: The number of instructions the machines need to use. 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 . 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,
5100-572: The queue by removing the node at the head of r {\displaystyle r} . When r {\displaystyle r} is empty, the list f {\displaystyle f} is reversed and assigned to r {\displaystyle r} and then the head of r {\displaystyle r} is removed. The insert ("enqueue") always takes O ( 1 ) {\displaystyle O(1)} time. The removal ("dequeue") takes O ( 1 ) {\displaystyle O(1)} when
5175-552: 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
5250-646: The same function is running across multiple areas of data ( data parallelism ) or different tasks can be performed simultaneously with limited interaction ( task parallelism ). 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). Microarchitecture , also known as computer organization, refers to high-level hardware questions such as
5325-454: 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. Common types of ISAs include CISC ( complex instruction set computer ), RISC ( reduced instruction set computer ), vector operations , and hybrid modes. CISC involves using a larger expression set to minimize
5400-445: The system's performance. Computer architecture requires prioritizing between different goals, such as cost, speed, availability, and energy efficiency. The designer must have a good grasp of the hardware requirements and many different aspects of computing, from compilers to integrated circuit design. Cost has also become a significant constraint for manufacturers seeking to sell their products for less money than competitors offering
5475-449: The unit. Hobbyists may decorate the cases with colored lights, paint, or other features, in an activity called case modding . 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. The motherboard
5550-416: The words used when people line up to wait for goods or services. The operation of adding an element to the rear of the queue is known as enqueue , and the operation of removing an element from the front is known as dequeue . Other operations may also be allowed, often including a peek or front operation that returns the value of the next element to be dequeued without dequeuing it. The operations of
5625-451: 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. Even prior to this, in the mid-19th century mathematician George Boole invented Boolean algebra —a system of logic where each proposition
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