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84-631: In computing , Machine Check Architecture ( MCA ) is an Intel and AMD mechanism in which the CPU reports hardware errors to the operating system . Intel 's P6 and Pentium 4 family processors, AMD 's K7 and K8 family processors, as well as the Itanium architecture implement a machine check architecture that provides a mechanism for detecting and reporting hardware (machine) errors, such as: system bus errors, ECC errors, parity errors, cache errors, and translation lookaside buffer errors. It consists of

168-429: A depletion layer by forcing the positively charged holes away from the gate-insulator/semiconductor interface, leaving exposed a carrier-free region of immobile, negatively charged acceptor ions (see doping ). If V G is high enough, a high concentration of negative charge carriers forms in an inversion layer located in a thin layer next to the interface between the semiconductor and the insulator. Conventionally,

252-564: A MOSFET. In the case of a p-type MOSFET, bulk inversion happens when the intrinsic energy level at the surface becomes smaller than the Fermi level at the surface. This can be seen on a band diagram. The Fermi level defines the type of semiconductor in discussion. If the Fermi level is equal to the Intrinsic level, the semiconductor is of intrinsic, or pure type. If the Fermi level lies closer to

336-535: A bipolar transistor. The subthreshold I–V curve depends exponentially upon threshold voltage, introducing a strong dependence on any manufacturing variation that affects threshold voltage; for example: variations in oxide thickness, junction depth, or body doping that change the degree of drain-induced barrier lowering. The resulting sensitivity to fabricational variations complicates optimization for leakage and performance. When V GS > V th and V DS < V GS  − V th : The transistor

420-491: A broad array of electronic, wireless, and optical networking technologies. The Internet carries an extensive range of information resources and services, such as the inter-linked hypertext documents of the World Wide Web and the infrastructure to support email. Computer programming is the process of writing, testing, debugging, and maintaining the source code and documentation of computer programs. This source code

504-404: A buried oxide is formed below a thin semiconductor layer. If the channel region between the gate dielectric and the buried oxide region is very thin, the channel is referred to as an ultrathin channel region with the source and drain regions formed on either side in or above the thin semiconductor layer. Other semiconductor materials may be employed. When the source and drain regions are formed above

588-434: A computer program. Instructions express the computations performed by the computer. They trigger sequences of simple actions on the executing machine. Those actions produce effects according to the semantics of the instructions. Computer hardware includes the physical parts of a computer, including the central processing unit , memory , and input/output . Computational logic and computer architecture are key topics in

672-497: A computer's capabilities, but typically do not directly apply them in the performance of tasks that benefit the user, unlike application software. Application software, also known as an application or an app , is computer software designed to help the user perform specific tasks. Examples include enterprise software , accounting software , office suites , graphics software , and media players . Many application programs deal principally with documents . Apps may be bundled with

756-476: A long-channel device, there is no drain voltage dependence of the current once V DS ≫ V T {\displaystyle V_{\text{DS}}\gg V_{\text{T}}} , but as channel length is reduced drain-induced barrier lowering introduces drain voltage dependence that depends in a complex way upon the device geometry (for example, the channel doping, the junction doping and so on). Frequently, threshold voltage V th for this mode

840-455: A set of model-specific registers ( MSRs ) that are used to set up machine checking and additional banks of MSRs used for recording errors that are detected. This computer hardware article is a stub . You can help Misplaced Pages by expanding it . Computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery . It includes the study and experimentation of algorithmic processes, and

924-480: A silicon MOS transistor in 1959 and successfully demonstrated a working MOS device with their Bell Labs team in 1960. Their team included E. E. LaBate and E. I. Povilonis who fabricated the device; M. O. Thurston, L. A. D’Asaro, and J. R. Ligenza who developed the diffusion processes, and H. K. Gummel and R. Lindner who characterized the device. This was a culmination of decades of field-effect research that began with Lilienfeld. The first MOS transistor at Bell Labs

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1008-511: A similar device in Europe. In the 1940s, Bell Labs scientists William Shockley , John Bardeen and Walter Houser Brattain attempted to build a field-effect device, which led to their discovery of the transistor effect. However, the structure failed to show the anticipated effects, due to the problem of surface states : traps on the semiconductor surface that hold electrons immobile. With no surface passivation , they were only able to build

1092-435: A superposition, i.e. in both states of one and zero, simultaneously. Thus, the value of the qubit is not between 1 and 0, but changes depending on when it is measured. This trait of qubits is known as quantum entanglement , and is the core idea of quantum computing that allows quantum computers to do large scale computations. Quantum computing is often used for scientific research in cases where traditional computers do not have

1176-417: A team demonstrated a working MOSFET at Bell Labs 1960. The MOSFET made it possible to build high-density integrated circuits , leading to what is known as the computer revolution or microcomputer revolution . A computer is a machine that manipulates data according to a set of instructions called a computer program . The program has an executable form that the computer can use directly to execute

1260-421: Is spintronics . Spintronics can provide computing power and storage, without heat buildup. Some research is being done on hybrid chips, which combine photonics and spintronics. There is also research ongoing on combining plasmonics , photonics, and electronics. Cloud computing is a model that allows for the use of computing resources, such as servers or applications, without the need for interaction between

1344-460: Is a discipline that integrates several fields of electrical engineering and computer science required to develop computer hardware and software. Computer engineers usually have training in electronic engineering (or electrical engineering ), software design , and hardware-software integration, rather than just software engineering or electronic engineering. Computer engineers are involved in many hardware and software aspects of computing, from

1428-414: Is a person who writes computer software. The term computer programmer can refer to a specialist in one area of computer programming or to a generalist who writes code for many kinds of software. One who practices or professes a formal approach to programming may also be known as a programmer analyst. A programmer's primary computer language ( C , C++ , Java , Lisp , Python , etc.) is often prefixed to

1512-748: Is a weak-inversion current, sometimes called subthreshold leakage. In weak inversion where the source is tied to bulk, the current varies exponentially with V GS {\displaystyle V_{\text{GS}}} as given approximately by: I D ≈ I D0 e V GS − V th n V T , {\displaystyle I_{\text{D}}\approx I_{\text{D0}}e^{\frac {V_{\text{GS}}-V_{\text{th}}}{nV_{\text{T}}}},} where I D0 {\displaystyle I_{\text{D0}}} = current at V GS = V th {\displaystyle V_{\text{GS}}=V_{\text{th}}} ,

1596-414: Is an area of research that brings together the disciplines of computer science, information theory, and quantum physics. While the idea of information as part of physics is relatively new, there appears to be a strong tie between information theory and quantum mechanics. Whereas traditional computing operates on a binary system of ones and zeros, quantum computing uses qubits . Qubits are capable of being in

1680-501: Is by far the most common transistor in digital circuits, as billions may be included in a memory chip or microprocessor. Since MOSFETs can be made with either p-type or n-type semiconductors, complementary pairs of MOS transistors can be used to make switching circuits with very low power consumption, in the form of CMOS logic . The basic principle of the field-effect transistor was first patented by Julius Edgar Lilienfeld in 1925. In 1934, inventor Oskar Heil independently patented

1764-423: Is computer software designed to operate and control computer hardware, and to provide a platform for running application software. System software includes operating systems , utility software , device drivers , window systems , and firmware . Frequently used development tools such as compilers , linkers , and debuggers are classified as system software. System software and middleware manage and integrate

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1848-714: Is defined as the gate voltage at which a selected value of current I D0 occurs, for example, I D0 = 1   μA, which may not be the same V th -value used in the equations for the following modes. Some micropower analog circuits are designed to take advantage of subthreshold conduction. By working in the weak-inversion region, the MOSFETs in these circuits deliver the highest possible transconductance-to-current ratio, namely: g m / I D = 1 / ( n V T ) {\displaystyle g_{m}/I_{\text{D}}=1/\left(nV_{\text{T}}\right)} , almost that of

1932-476: Is denoted CMOS-integrated nanophotonics (CINP). One benefit of optical interconnects is that motherboards, which formerly required a certain kind of system on a chip (SoC), can now move formerly dedicated memory and network controllers off the motherboards, spreading the controllers out onto the rack. This allows standardization of backplane interconnects and motherboards for multiple types of SoCs, which allows more timely upgrades of CPUs. Another field of research

2016-415: Is equivalent to a planar capacitor , with one of the electrodes replaced by a semiconductor. When a voltage is applied across a MOS structure, it modifies the distribution of charges in the semiconductor. If we consider a p-type semiconductor (with N A the density of acceptors , p the density of holes; p = N A in neutral bulk), a positive voltage, V G , from gate to body (see figure) creates

2100-710: Is its potential to support energy efficiency. Allowing thousands of instances of computation to occur on one single machine instead of thousands of individual machines could help save energy. It could also ease the transition to renewable energy source, since it would suffice to power one server farm with renewable energy, rather than millions of homes and offices. However, this centralized computing model poses several challenges, especially in security and privacy. Current legislation does not sufficiently protect users from companies mishandling their data on company servers. This suggests potential for further legislative regulations on cloud computing and tech companies. Quantum computing

2184-559: Is sometimes considered a sub-discipline of electrical engineering , telecommunications, computer science , information technology, or computer engineering , since it relies upon the theoretical and practical application of these disciplines. The Internet is a global system of interconnected computer networks that use the standard Internet Protocol Suite (TCP/IP) to serve billions of users. This includes millions of private, public, academic, business, and government networks, ranging in scope from local to global. These networks are linked by

2268-531: Is the abacus , and it is thought to have been invented in Babylon circa between 2700 and 2300 BC. Abaci, of a more modern design, are still used as calculation tools today. The first recorded proposal for using digital electronics in computing was the 1931 paper "The Use of Thyratrons for High Speed Automatic Counting of Physical Phenomena" by C. E. Wynn-Williams . Claude Shannon 's 1938 paper " A Symbolic Analysis of Relay and Switching Circuits " then introduced

2352-687: Is the application of computers and telecommunications equipment to store, retrieve, transmit, and manipulate data, often in the context of a business or other enterprise. The term is commonly used as a synonym for computers and computer networks, but also encompasses other information distribution technologies such as television and telephones. Several industries are associated with information technology, including computer hardware, software, electronics , semiconductors , internet, telecom equipment , e-commerce , and computer services . DNA-based computing and quantum computing are areas of active research for both computing hardware and software, such as

2436-501: Is the charge-carrier effective mobility, W {\displaystyle W} is the gate width, L {\displaystyle L} is the gate length and C ox {\displaystyle C_{\text{ox}}} is the gate oxide capacitance per unit area. The transition from the exponential subthreshold region to the triode region is not as sharp as the equations suggest. When V GS > V th and V DS ≥ (V GS  – V th ): The switch

2520-509: Is the study of complementary networks of hardware and software (see information technology) that people and organizations use to collect, filter, process, create, and distribute data . The ACM 's Computing Careers describes IS as: "A majority of IS [degree] programs are located in business schools; however, they may have different names such as management information systems, computer information systems, or business information systems. All IS degrees combine business and computing topics, but

2604-449: Is thus often developed by a team of domain experts, each a specialist in some area of development. However, the term programmer may apply to a range of program quality, from hacker to open source contributor to professional. It is also possible for a single programmer to do most or all of the computer programming needed to generate the proof of concept to launch a new killer application . A programmer, computer programmer, or coder

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2688-787: Is turned on, and a channel has been created which allows current between the drain and the source. The MOSFET operates like a resistor, controlled by the gate voltage relative to both the source and drain voltages. The current from drain to source is modeled as: I D = μ n C ox W L ( ( V GS − V t h ) V DS − V DS 2 2 ) {\displaystyle I_{\text{D}}=\mu _{n}C_{\text{ox}}{\frac {W}{L}}\left(\left(V_{\text{GS}}-V_{\rm {th}}\right)V_{\text{DS}}-{\frac {{V_{\text{DS}}}^{2}}{2}}\right)} where μ n {\displaystyle \mu _{n}}

2772-427: Is turned on, and a channel has been created, which allows current between the drain and source. Since the drain voltage is higher than the source voltage, the electrons spread out, and conduction is not through a narrow channel but through a broader, two- or three-dimensional current distribution extending away from the interface and deeper in the substrate. The onset of this region is also known as pinch-off to indicate

2856-429: Is written in a programming language , which is an artificial language that is often more restrictive than natural languages , but easily translated by the computer. Programming is used to invoke some desired behavior (customization) from the machine. Writing high-quality source code requires knowledge of both the computer science domain and the domain in which the application will be used. The highest-quality software

2940-447: The 45 nanometer node. When a voltage is applied between the gate and the source, the electric field generated penetrates through the oxide and creates an inversion layer or channel at the semiconductor-insulator interface. The inversion layer provides a channel through which current can pass between source and drain terminals. Varying the voltage between the gate and body modulates the conductivity of this layer and thereby controls

3024-455: The BJT and thyristor transistors. In 1955, Carl Frosch and Lincoln Derick accidentally grew a layer of silicon dioxide over the silicon wafer, for which they observed surface passivation effects. By 1957 Frosch and Derick, using masking and predeposition, were able to manufacture silicon dioxide field effect transistors; the first planar transistors, in which drain and source were adjacent at

3108-466: The Manchester Baby . However, early junction transistors were relatively bulky devices that were difficult to mass-produce, which limited them to a number of specialised applications. In 1957, Frosch and Derick were able to manufacture the first silicon dioxide field effect transistors at Bell Labs, the first transistors in which drain and source were adjacent at the surface. Subsequently,

3192-444: The function of the program it implements, either by directly providing instructions to the computer hardware or by serving as input to another piece of software. The term was coined to contrast with the old term hardware (meaning physical devices). In contrast to hardware, software is intangible. Software is also sometimes used in a more narrow sense, meaning application software only. System software, or systems software,

3276-432: The Fermi level and when the voltage reaches the threshold voltage, the intrinsic level does cross the Fermi level, and that is what is known as inversion. At that point, the surface of the semiconductor is inverted from p-type into n-type. If the Fermi level lies above the intrinsic level, the semiconductor is of n-type, therefore at inversion, when the intrinsic level reaches and crosses the Fermi level (which lies closer to

3360-880: The above titles, and those who work in a web environment often prefix their titles with Web . The term programmer can be used to refer to a software developer , software engineer, computer scientist , or software analyst . However, members of these professions typically possess other software engineering skills, beyond programming. The computer industry is made up of businesses involved in developing computer software, designing computer hardware and computer networking infrastructures, manufacturing computer components, and providing information technology services, including system administration and maintenance. The software industry includes businesses engaged in development , maintenance , and publication of software. The industry also includes software services , such as training , documentation , and consulting. Computer engineering

3444-463: The addition of n-type source and drain regions. The MOS capacitor structure is the heart of the MOSFET. Consider a MOS capacitor where the silicon base is of p-type. If a positive voltage is applied at the gate, holes which are at the surface of the p-type substrate will be repelled by the electric field generated by the voltage applied. At first, the holes will simply be repelled and what will remain on

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3528-448: The body) are highly doped as signified by a "+" sign after the type of doping. If the MOSFET is an n-channel or nMOS FET, then the source and drain are n+ regions and the body is a p region. If the MOSFET is a p-channel or pMOS FET, then the source and drain are p+ regions and the body is a n region. The source is so named because it is the source of the charge carriers (electrons for n-channel, holes for p-channel) that flow through

3612-457: The challenges in implementing computations. For example, programming language theory studies approaches to the description of computations, while the study of computer programming investigates the use of programming languages and complex systems . The field of human–computer interaction focuses on the challenges in making computers and computations useful, usable, and universally accessible to humans. The field of cybersecurity pertains to

3696-406: The channel in whole or in part, they are referred to as raised source/drain regions. The operation of a MOSFET can be separated into three different modes, depending on the voltages at the terminals. In the following discussion, a simplified algebraic model is used. Modern MOSFET characteristics are more complex than the algebraic model presented here. For an enhancement-mode, n-channel MOSFET ,

3780-408: The channel; similarly, the drain is where the charge carriers leave the channel. The occupancy of the energy bands in a semiconductor is set by the position of the Fermi level relative to the semiconductor energy-band edges. With sufficient gate voltage, the valence band edge is driven far from the Fermi level, and holes from the body are driven away from the gate. At larger gate bias still, near

3864-560: The computer and its system software, or may be published separately. Some users are satisfied with the bundled apps and need never install additional applications. The system software manages the hardware and serves the application, which in turn serves the user. Application software applies the power of a particular computing platform or system software to a particular purpose. Some apps, such as Microsoft Office , are developed in multiple versions for several different platforms; others have narrower requirements and are generally referred to by

3948-510: The computing power to do the necessary calculations, such in molecular modeling . Large molecules and their reactions are far too complex for traditional computers to calculate, but the computational power of quantum computers could provide a tool to perform such calculations. MOSFET The main advantage of a MOSFET is that it requires almost no input current to control the load current, when compared to bipolar junction transistors (BJTs). In an enhancement mode MOSFET, voltage applied to

4032-414: The conduction band (valence band) then the semiconductor type will be of n-type (p-type). When the gate voltage is increased in a positive sense (for the given example), this will shift the intrinsic energy level band so that it will curve downwards towards the valence band. If the Fermi level lies closer to the valence band (for p-type), there will be a point when the Intrinsic level will start to cross

4116-422: The current flow between drain and source. This is known as enhancement mode. The traditional metal–oxide–semiconductor (MOS) structure is obtained by growing a layer of silicon dioxide ( SiO 2 ) on top of a silicon substrate, commonly by thermal oxidation and depositing a layer of metal or polycrystalline silicon (the latter is commonly used). As silicon dioxide is a dielectric material, its structure

4200-731: The depletion layer and C ox {\displaystyle C_{\text{ox}}} = capacitance of the oxide layer. This equation is generally used, but is only an adequate approximation for the source tied to the bulk. For the source not tied to the bulk, the subthreshold equation for drain current in saturation is I D ≈ I D0 e V G − V th n V T e − V S V T . {\displaystyle I_{\text{D}}\approx I_{\text{D0}}e^{\frac {V_{\text{G}}-V_{\text{th}}}{nV_{\text{T}}}}e^{-{\frac {V_{\text{S}}}{V_{\text{T}}}}}.} In

4284-448: The design of individual microprocessors , personal computers, and supercomputers , to circuit design . This field of engineering includes not only the design of hardware within its own domain, but also the interactions between hardware and the context in which it operates. Software engineering is the application of a systematic, disciplined, and quantifiable approach to the design, development, operation, and maintenance of software, and

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4368-414: The development of quantum algorithms . Potential infrastructure for future technologies includes DNA origami on photolithography and quantum antennae for transferring information between ion traps. By 2011, researchers had entangled 14 qubits . Fast digital circuits , including those based on Josephson junctions and rapid single flux quantum technology, are becoming more nearly realizable with

4452-427: The development of both hardware and software. Computing has scientific, engineering, mathematical, technological, and social aspects. Major computing disciplines include computer engineering , computer science , cybersecurity , data science , information systems , information technology , and software engineering . The term computing is also synonymous with counting and calculating . In earlier times, it

4536-467: The device may be referred to as a metal-insulator-semiconductor FET (MISFET). Compared to the MOS capacitor, the MOSFET includes two additional terminals ( source and drain ), each connected to individual highly doped regions that are separated by the body region. These regions can be either p or n type, but they must both be of the same type, and of opposite type to the body region. The source and drain (unlike

4620-437: The discovery of nanoscale superconductors . Fiber-optic and photonic (optical) devices, which already have been used to transport data over long distances, are starting to be used by data centers, along with CPU and semiconductor memory components. This allows the separation of RAM from CPU by optical interconnects. IBM has created an integrated circuit with both electronic and optical information processing in one chip. This

4704-468: The effect of thermal energy on the Fermi–Dirac distribution of electron energies which allow some of the more energetic electrons at the source to enter the channel and flow to the drain. This results in a subthreshold current that is an exponential function of gate-source voltage. While the current between drain and source should ideally be zero when the transistor is being used as a turned-off switch, there

4788-424: The electron is now fixed onto the atom and immobile. As the voltage at the gate increases, there will be a point at which the surface above the depletion region will be converted from p-type into n-type, as electrons from the bulk area will start to get attracted by the larger electric field. This is known as inversion . The threshold voltage at which this conversion happens is one of the most important parameters in

4872-686: The emphasis between technical and organizational issues varies among programs. For example, programs differ substantially in the amount of programming required." The study of IS bridges business and computer science , using the theoretical foundations of information and computation to study various business models and related algorithmic processes within a computer science discipline. The field of Computer Information Systems (CIS) studies computers and algorithmic processes, including their principles, their software and hardware designs, their applications, and their impact on society while IS emphasizes functionality over design. Information technology (IT)

4956-665: The engineering paradigm. The generally accepted concepts of Software Engineering as an engineering discipline have been specified in the Guide to the Software Engineering Body of Knowledge (SWEBOK). The SWEBOK has become an internationally accepted standard in ISO/IEC TR 19759:2015. Computer science or computing science (abbreviated CS or Comp Sci) is the scientific and practical approach to computation and its applications. A computer scientist specializes in

5040-434: The field of computer hardware. Computer software, or just software , is a collection of computer programs and related data, which provides instructions to a computer. Software refers to one or more computer programs and data held in the storage of the computer. It is a set of programs, procedures, algorithms, as well as its documentation concerned with the operation of a data processing system. Program software performs

5124-413: The gate leads to a higher electron density in the inversion layer and therefore increases the current flow between the source and drain. For gate voltages below the threshold value, the channel is lightly populated, and only a very small subthreshold leakage current can flow between the source and the drain. When a negative gate-source voltage (positive source-gate) is applied, it creates a p-channel at

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5208-476: The gate terminal increases the conductivity of the device. In depletion mode transistors, voltage applied at the gate reduces the conductivity. The "metal" in the name MOSFET is sometimes a misnomer , because the gate material can be a layer of polysilicon (polycrystalline silicon). Similarly, "oxide" in the name can also be a misnomer, as different dielectric materials are used with the aim of obtaining strong channels with smaller applied voltages. The MOSFET

5292-408: The gate voltage at which the volume density of electrons in the inversion layer is the same as the volume density of holes in the body is called the threshold voltage . When the voltage between transistor gate and source ( V G ) exceeds the threshold voltage ( V th ), the difference is known as overdrive voltage . This structure with p-type body is the basis of the n-type MOSFET, which requires

5376-476: The idea of using electronics for Boolean algebraic operations. The concept of a field-effect transistor was proposed by Julius Edgar Lilienfeld in 1925. John Bardeen and Walter Brattain , while working under William Shockley at Bell Labs , built the first working transistor , the point-contact transistor , in 1947. In 1953, the University of Manchester built the first transistorized computer ,

5460-417: The increase in power consumption due to gate current leakage, a high-κ dielectric is used instead of silicon dioxide for the gate insulator, while polysilicon is replaced by metal gates (e.g. Intel , 2009). The gate is separated from the channel by a thin insulating layer, traditionally of silicon dioxide and later of silicon oxynitride . Some companies use a high-κ dielectric and metal gate combination in

5544-400: The instructions. The same program in its human-readable source code form, enables a programmer to study and develop a sequence of steps known as an algorithm . Because the instructions can be carried out in different types of computers, a single set of source instructions converts to machine instructions according to the CPU type. The execution process carries out the instructions in

5628-818: The lack of channel region near the drain. Although the channel does not extend the full length of the device, the electric field between the drain and the channel is very high, and conduction continues. The drain current is now weakly dependent upon drain voltage and controlled primarily by the gate-source voltage, and modeled approximately as: I D = μ n C ox 2 W L [ V GS − V th ] 2 [ 1 + λ V DS ] . {\displaystyle I_{\text{D}}={\frac {\mu _{n}C_{\text{ox}}}{2}}{\frac {W}{L}}\left[V_{\text{GS}}-V_{\text{th}}\right]^{2}\left[1+\lambda V_{\text{DS}}\right].} The additional factor involving λ,

5712-460: The owner of these resources and the end user. It is typically offered as a service, making it an example of Software as a Service , Platforms as a Service , and Infrastructure as a Service , depending on the functionality offered. Key characteristics include on-demand access, broad network access, and the capability of rapid scaling. It allows individual users or small business to benefit from economies of scale . One area of interest in this field

5796-480: The platform they run on. For example, a geography application for Windows or an Android application for education or Linux gaming . Applications that run only on one platform and increase the desirability of that platform due to the popularity of the application, known as killer applications . A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow

5880-495: The preprint of their article in December 1956 to all his senior staff, including Jean Hoerni , who would later invent the planar process in 1959 while at Fairchild Semiconductor . After this, J.R. Ligenza and W.G. Spitzer studied the mechanism of thermally grown oxides, fabricated a high quality Si/ SiO 2 stack and published their results in 1960. Following this research, Mohamed Atalla and Dawon Kahng proposed

5964-522: The protection of computer systems and networks. This includes information and data privacy , preventing disruption of IT services and prevention of theft of and damage to hardware, software, and data. Data science is a field that uses scientific and computing tools to extract information and insights from data, driven by the increasing volume and availability of data. Data mining , big data , statistics, machine learning and deep learning are all interwoven with data science. Information systems (IS)

6048-606: The rules and data formats for exchanging information in a computer network, and provide the basis for network programming . One well-known communications protocol is Ethernet , a hardware and link layer standard that is ubiquitous in local area networks . Another common protocol is the Internet Protocol Suite , which defines a set of protocols for internetworking, i.e. for data communication between multiple networks, host-to-host data transfer, and application-specific data transmission formats. Computer networking

6132-404: The same surface. They showed that silicon dioxide insulated, protected silicon wafers and prevented dopants from diffusing into the wafer. At Bell Labs, the importance of Frosch and Derick technique and transistors was immediately realized. Results of their work circulated around Bell Labs in the form of BTL memos before being published in 1957. At Shockley Semiconductor , Shockley had circulated

6216-399: The semiconductor surface the conduction band edge is brought close to the Fermi level, populating the surface with electrons in an inversion layer or n-channel at the interface between the p region and the oxide. This conducting channel extends between the source and the drain, and current is conducted through it when a voltage is applied between the two electrodes. Increasing the voltage on

6300-454: The sharing of resources and information. When at least one process in one device is able to send or receive data to or from at least one process residing in a remote device, the two devices are said to be in a network. Networks may be classified according to a wide variety of characteristics such as the medium used to transport the data, communications protocol used, scale, topology , and organizational scope. Communications protocols define

6384-442: The study of these approaches. That is, the application of engineering to software. It is the act of using insights to conceive, model and scale a solution to a problem. The first reference to the term is the 1968 NATO Software Engineering Conference , and was intended to provoke thought regarding the perceived software crisis at the time. Software development , a widely used and more generic term, does not necessarily subsume

6468-418: The surface of the n region, analogous to the n-channel case, but with opposite polarities of charges and voltages. When a voltage less negative than the threshold value (a negative voltage for the p-channel) is applied between gate and source, the channel disappears and only a very small subthreshold current can flow between the source and the drain. The device may comprise a silicon on insulator device in which

6552-410: The surface will be immobile (negative) atoms of the acceptor type, which creates a depletion region on the surface. A hole is created by an acceptor atom, e.g., boron, which has one less electron than a silicon atom. Holes are not actually repelled, being non-entities; electrons are attracted by the positive field, and fill these holes. This creates a depletion region where no charge carriers exist because

6636-446: The theory of computation and the design of computational systems. Its subfields can be divided into practical techniques for its implementation and application in computer systems , and purely theoretical areas. Some, such as computational complexity theory , which studies fundamental properties of computational problems , are highly abstract, while others, such as computer graphics , emphasize real-world applications. Others focus on

6720-417: The thermal voltage V T = k T / q {\displaystyle V_{\text{T}}=kT/q} and the slope factor n is given by: n = 1 + C dep C ox , {\displaystyle n=1+{\frac {C_{\text{dep}}}{C_{\text{ox}}}},} with C dep {\displaystyle C_{\text{dep}}} = capacitance of

6804-443: The three operational modes are: When V GS < V th : where V GS {\displaystyle V_{\text{GS}}} is gate-to-source bias and V th {\displaystyle V_{\text{th}}} is the threshold voltage of the device. According to the basic threshold model, the transistor is turned off, and there is no conduction between drain and source. A more accurate model considers

6888-421: The valence band), the semiconductor type changes at the surface as dictated by the relative positions of the Fermi and Intrinsic energy levels. A MOSFET is based on the modulation of charge concentration by a MOS capacitance between a body electrode and a gate electrode located above the body and insulated from all other device regions by a gate dielectric layer. If dielectrics other than an oxide are employed,

6972-748: Was about 100 times slower than contemporary bipolar transistors and was initially seen as inferior. Nevertheless, Kahng pointed out several advantages of the device, notably ease of fabrication and its application in integrated circuits . Usually the semiconductor of choice is silicon . Some chip manufacturers, most notably IBM and Intel , use an alloy of silicon and germanium ( SiGe ) in MOSFET channels. Many semiconductors with better electrical properties than silicon, such as gallium arsenide , do not form good semiconductor-to-insulator interfaces, and thus are not suitable for MOSFETs. Research continues on creating insulators with acceptable electrical characteristics on other semiconductor materials. To overcome

7056-519: Was used in reference to the action performed by mechanical computing machines , and before that, to human computers . The history of computing is longer than the history of computing hardware and includes the history of methods intended for pen and paper (or for chalk and slate) with or without the aid of tables. Computing is intimately tied to the representation of numbers, though mathematical concepts necessary for computing existed before numeral systems . The earliest known tool for use in computation

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