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Cloud computing is the on-demand availability of
computer A computer is a machine that can be programmed to Execution (computing), carry out sequences of arithmetic or logical operations automatically. Modern computers can perform generic sets of operations known as Computer program, programs. These ...

computer
system resource In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes and development of both computer hardware , hardware and softw ...
s, especially data storage (
cloud storage Cloud storage is a model of computer data storage in which the digital data is stored in logical Pool (computer science), pools, said to be on "the cloud". The storage virtualization, physical storage spans multiple Server (computing), servers (so ...
) and
computing power In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes and development of both computer hardware , hardware and softwar ...
, without direct active management by the user. Large clouds often have functions
distributedDistribution may refer to: Mathematics *Distribution (mathematics) Distributions, also known as Schwartz distributions or generalized functions, are objects that generalize the classical notion of functions in mathematical analysis. Distr ...
over multiple locations, each location being a data center. Cloud computing relies on sharing of resources to achieve coherence and
economies of scale 330px, As quantity of production increases from Q to Q2, the average cost of each unit decreases from C to C1. LRAC is the long-run average cost In microeconomics, economies of scale are the cost advantages that enterprises obtain due to their sca ...

economies of scale
, typically using a "pay-as-you-go" model which can help in reducing capital expenses but may also lead to unexpected
operating expense An operating expense, operating expenditure, operational expense, operational expenditure or opex is an ongoing cost for running a product, business, or system . Its counterpart, a capital expenditure Capital expenditure or capital expense (cap ...
s for unaware users.


Value proposition

Advocates of public and hybrid clouds note that cloud computing allows companies to avoid or minimize up-front
IT infrastructure Information technology infrastructure is defined broadly as a set of information technology (IT) components that are the foundation of an IT service; typically physical components (Computer hardware, computer and networking hardware and facilitie ...
costs. Proponents also claim that cloud computing allows
enterprises
enterprises
to get their applications up and running faster, with improved manageability and less maintenance, and that it enables IT teams to more rapidly adjust resources to meet fluctuating and unpredictable demand, providing the burst computing capability: high computing power at certain periods of peak demand.


History

References to the phrase "cloud computing" appeared as early as 1996, with the first known mention in a
Compaq Compaq (a portmanteau A portmanteau (, ) or portmanteau word (from "portmanteau (luggage) A portmanteau is a piece of luggage Baggage or luggage consists of bags, cases, and containers which hold a travel Travel is the movement ...

Compaq
internal document. The cloud symbol was used to represent networks of computing equipment in the original
ARPANET The Advanced Research Projects Agency Network (ARPANET) was the first wide-area packet-switching In telecommunications, packet switching is a method of grouping data that is transmitted over a digital network into '' packets''. Packets are ...
by as early as 1977, and the
CSNETThe Computer Science Network (CSNET) was a computer network that began operation in 1981 in the United States. Its purpose was to extend networking benefits, for computer science departments at academic and research institutions that could not be dir ...
by 1981—both predecessors to the Internet itself. The word ''cloud'' was used as a
metaphor A metaphor is a figure of speech A figure of speech or rhetorical figure is a word or phrase that entails an intentional deviation from ordinary language use in order to produce a rhetoric Rhetoric () is the Art (skill), art of ...
for the Internet and a standardized cloud-like shape was used to denote a network on
telephony Telephony ( ) is the field of technology involving the development, application, and deployment of telecommunication services for the purpose of electronic transmission of voice, fax, or data, between distant parties. The history of telephony is i ...
schematics. With this simplification, the implication is that the specifics of how the endpoints of a network are connected are not relevant to understanding the diagram. The term ''cloud'' was used to refer to platforms for
distributed computing Distributed computing is a field of computer science Computer science deals with the theoretical foundations of information, algorithms and the architectures of its computation as well as practical techniques for their application. Comp ...
as early as 1993, when
Apple An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple fruit tree, trees are agriculture, cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, wher ...
spin-off
General Magic General Magic was an American software Software is a collection of instructions that tell a computer A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations automatically. Modern comput ...
and
AT&T AT&T Inc. is an American multinational Multinational may refer to: * Multinational corporation, a corporate organization operating in multiple countries * Multinational force, a military body from multiple countries * Multinational state, a s ...

AT&T
used it in describing their (paired) Telescript and PersonaLink technologies. In '' Wired's'' April 1994 feature "Bill and Andy's Excellent Adventure II",
Andy Hertzfeld Andrew Jay Hertzfeld (born April 6, 1953) is an American software engineer and innovator who was a member of the original Apple Macintosh development team during the 1980s. After buying an Apple II in January 1978, he went to work for A ...
commented on Telescript, General Magic's distributed programming language:


Early history

During the 1960s, the initial concepts of
time-sharing In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes and development of both computer hardware , hardware and softw ...
became popularized via RJE (
Remote Job EntryRemote job entry is the procedure for sending requests for non-interactive data processing tasks ( jobs) to mainframe computer A mainframe computer, informally called a mainframe or big iron, is a computer A computer is a machine that can ...
); this terminology was mostly associated with large vendors such as
IBM International Business Machines Corporation (IBM) is an American multinational technology company headquartered in Armonk, New York, with operations in over 170 countries. The company began in 1911, founded in Endicott, New York, as the C ...

IBM
and DEC. Full-time-sharing solutions were available by the early 1970s on such platforms as Multics (on GE hardware), Cambridge CTSS, and the earliest UNIX ports (on DEC hardware). Yet, the "data center" model where users submitted jobs to operators to run on IBM's mainframes was overwhelmingly predominant. In the 1990s, telecommunications companies, who previously offered primarily dedicated point-to-point data circuits, began offering
virtual private network A virtual private network (VPN) extends a private network In IP network The Internet protocol suite is the Conceptual model (computer science), conceptual model and set of communications protocols used in the Internet and similar comput ...
(VPN) services with comparable quality of service, but at a lower cost. By switching traffic as they saw fit to balance server use, they could use overall network bandwidth more effectively. They began to use the cloud symbol to denote the demarcation point between what the provider was responsible for and what users were responsible for. Cloud computing extended this boundary to cover all servers as well as the network infrastructure. As computers became more diffused, scientists and technologists explored ways to make large-scale computing power available to more users through time-sharing. They experimented with algorithms to optimize the infrastructure, platform, and applications to prioritize CPUs and increase efficiency for end users. The use of the cloud metaphor for virtualized services dates at least to
General Magic General Magic was an American software Software is a collection of instructions that tell a computer A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations automatically. Modern comput ...
in 1994, where it was used to describe the universe of "places" that
mobile agentIn computer science Computer science deals with the theoretical foundations of information, algorithms and the architectures of its computation as well as practical techniques for their application. Computer science is the study of Algorith ...
s in the Telescript environment could go. As described by
Andy Hertzfeld Andrew Jay Hertzfeld (born April 6, 1953) is an American software engineer and innovator who was a member of the original Apple Macintosh development team during the 1980s. After buying an Apple II in January 1978, he went to work for A ...
: The use of the cloud metaphor is credited to General Magic communications employe
David Hoffman
based on long-standing use in networking and telecom. In addition to use by General Magic itself, it was also used in promoting
AT&T AT&T Inc. is an American multinational Multinational may refer to: * Multinational corporation, a corporate organization operating in multiple countries * Multinational force, a military body from multiple countries * Multinational state, a s ...

AT&T
's associated PersonaLink Services.


2000s

In July 2002,
Amazon Amazon usually refers to: * Amazons In Greek mythology, the Amazons (Ancient Greek: Ἀμαζόνες ''Amazónes'', singular Ἀμαζών ''Amazōn'') are portrayed in a number of ancient Greek, ancient epic poems and legends, such as the ...
created subsidiary
Amazon Web Services Amazon Web Services (AWS) is a subsidiary of Amazon Amazon usually refers to: * Amazons In Greek mythology, the Amazons (Ancient Greek: Ἀμαζόνες ''Amazónes'', singular Ἀμαζών ''Amazōn'') are portrayed in a number of an ...
, with the goal to "enable developers to build innovative and entrepreneurial applications on their own." In March 2006 Amazon introduced its Simple Storage Service (S3), followed by Elastic Compute Cloud (EC2) in August of the same year. These products pioneered the usage of server virtualization to deliver
IaaS Infrastructure as a service (IaaS) are online services that provide high-level API In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of ...
at a cheaper and on-demand pricing basis. In April 2008,
Google Google LLC is an American multinational Multinational may refer to: * Multinational corporation, a corporate organization operating in multiple countries * Multinational force, a military body from multiple countries * Multinational stat ...

Google
released the beta version of
Google App Engine Google App Engine (often referred to as GAE or simply App Engine) is a cloud computing platform as a service for developing and hosting web applications in Google-managed data centers. Applications are Sandbox (computer security), sandboxed and ru ...

Google App Engine
. The App Engine was a
PaaS Platform as a service (PaaS) or application platform as a service (aPaaS) or platform-based service is a category of cloud computing services that allows customers to provision, instantiate, run, and manage a modular bundle comprising a computing ...
(one of the first of its kind) which provided fully maintained infrastructure and a deployment platform for users to create web applications using common languages/technologies such as
Python PYTHON was a Cold War contingency plan of the Government of the United Kingdom, British Government for the continuity of government in the event of Nuclear warfare, nuclear war. Background Following the report of the Strath Committee in 1955, the ...
,
Node.js Node.js is an open-source, cross-platform In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes and development of ...
and
PHP PHP is a general-purpose scripting language A scripting language or script language is a programming language A programming language is a formal language comprising a Instruction set architecture, set of instructions that produce various k ...

PHP
. The goal was to eliminate the need for some administrative tasks typical of an
IaaS Infrastructure as a service (IaaS) are online services that provide high-level API In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of ...
model, while creating a platform where users could easily deploy such applications and
scale Scale or scales may refer to: Mathematics * Scale (descriptive set theory)In the mathematical discipline of descriptive set theory, a scale is a certain kind of object defined on a set (mathematics), set of point (mathematics), points in some Poli ...
them to demand. In early 2008,
NASA The National Aeronautics and Space Administration (NASA; ) is an independent agencies of the United States government, independent agency of the Federal government of the United States, U.S. federal government responsible for the civilian Li ...

NASA
's
Nebula A nebula ( for 'cloud' or 'fog'; pl. nebulae, nebulæ or nebulas) is a distinct body of s (which can consist of , , , ; possibly as ). Originally, the term was used to describe any diffused , including beyond the . The , for instance, was once ...
, enhanced in the RESERVOIR European Commission-funded project, became the first open-source software for deploying private and hybrid clouds, and for the federation of clouds. By mid-2008, Gartner saw an opportunity for cloud computing "to shape the relationship among consumers of IT services, those who use IT services and those who sell them" and observed that "organizations are switching from company-owned hardware and software assets to per-use service-based models" so that the "projected shift to computing ... will result in dramatic growth in IT products in some areas and significant reductions in other areas." In 2008, the U.S.
National Science Foundation The National Science Foundation (NSF) is an independent agency of the United States government Independent or Independents may refer to: Arts, entertainment, and media Artist groups * Independents (artist group)The Independents were a group of ...

National Science Foundation
began the Cluster Exploratory program to fund academic research using
Google Google LLC is an American multinational Multinational may refer to: * Multinational corporation, a corporate organization operating in multiple countries * Multinational force, a military body from multiple countries * Multinational stat ...

Google
-
IBM International Business Machines Corporation (IBM) is an American multinational technology company headquartered in Armonk, New York, with operations in over 170 countries. The company began in 1911, founded in Endicott, New York, as the C ...

IBM
cluster technology to analyze massive amounts of data. In 2009, the government of France announced Project Andromède to create a "sovereign cloud" or national cloud computing, with the government to spend €285 million. The initiative failed badly and
CloudwattCloudwatt was a core initiative of Project Andromède, one of France's periodic attempts at building a local computer industry. Project Andromède was announced in 2009 as a governmental desire for French-controlled cloud computing Cloud comp ...
was shut down on 1 February 2020.


2010s

In February 2010,
Microsoft Microsoft Corporation is an American multinational Multinational may refer to: * Multinational corporation, a corporate organization operating in multiple countries * Multinational force, a military body from multiple countries * Multination ...

Microsoft
released
Microsoft Azure Microsoft Azure, often referred to as Azure ( , ), is a cloud computing Cloud computing is the on-demand availability of computer A computer is a machine that can be programmed to carry out sequences of arithmetic or logical ...

Microsoft Azure
, which was announced in October 2008. In July 2010,
Rackspace Hosting
Rackspace Hosting
and
NASA The National Aeronautics and Space Administration (NASA; ) is an independent agencies of the United States government, independent agency of the Federal government of the United States, U.S. federal government responsible for the civilian Li ...

NASA
jointly launched an
open-source Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized softwar ...
cloud-software initiative known as
OpenStack OpenStack is a free Free may refer to: Concept * Freedom, having the ability to act or change without constraint * Emancipate, to procure political rights, as for a disenfranchised group * Free will, control exercised by rational agents over ...
. The OpenStack project intended to help organizations offering cloud-computing services running on standard hardware. The early code came from NASA's Nebula platform as well as from Rackspace's Cloud Files platform. As an open-source offering and along with other open-source solutions such as CloudStack, Ganeti, and OpenNebula, it has attracted attention by several key communities. Several studies aim at comparing these open source offerings based on a set of criteria. On March 1, 2011, IBM announced the
IBM SmartCloud IBM cloud computing is a set of cloud computing Cloud computing is the on-demand availability of computer system resources, especially data storage (cloud storage) and computing power, without direct active management by the user. The term i ...
framework to support Smarter Planet. Among the various components of the Smarter Computing foundation, cloud computing is a critical part. On June 7, 2012, Oracle announced the
Oracle Cloud Oracle Cloud is a cloud computing Cloud computing is the on-demand availability of computer system resources, especially data storage (cloud storage) and computing power, without direct active management by the user. The term is generally us ...
. This cloud offering is poised to be the first to provide users with access to an integrated set of IT solutions, including the Applications (
SaaS Software as a service (SaaS ) is a software licensing A software license is a legal instrument (usually by way of contract law A contract is a legally binding agreement that defines and governs the rights and duties between or among its P ...
), Platform (
PaaS Platform as a service (PaaS) or application platform as a service (aPaaS) or platform-based service is a category of cloud computing services that allows customers to provision, instantiate, run, and manage a modular bundle comprising a computing ...
), and Infrastructure (
IaaS Infrastructure as a service (IaaS) are online services that provide high-level API In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of ...
) layers. In May 2012,
Google Compute Engine Google Compute Engine (GCE) is the Infrastructure as a Service (IaaS) component of Google Cloud Platform which is built on the global infrastructure that runs Google's Google Search, search engine, Gmail, YouTube and other services. Google Comp ...
was released in preview, before being rolled out into General Availability in December 2013. In 2019, Linux was the most common OS used on
Microsoft Azure Microsoft Azure, often referred to as Azure ( , ), is a cloud computing Cloud computing is the on-demand availability of computer A computer is a machine that can be programmed to carry out sequences of arithmetic or logical ...

Microsoft Azure
. In December 2019,
Amazon Amazon usually refers to: * Amazons In Greek mythology, the Amazons (Ancient Greek: Ἀμαζόνες ''Amazónes'', singular Ἀμαζών ''Amazōn'') are portrayed in a number of ancient Greek, ancient epic poems and legends, such as the ...
announced
AWS Amazon Web Services (AWS) is a subsidiary of Amazon.com, Amazon providing Software as a service, on-demand cloud computing computing platform, platforms and Application programming interface, APIs to individuals, companies, and governments, on ...
Outposts, which is a fully managed service that extends AWS infrastructure, AWS services, APIs, and tools to virtually any customer datacenter, co-location space, or on-premises facility for a truly consistent hybrid experience


Similar concepts

The goal of cloud computing is to allow users to take benefit from all of these technologies, without the need for deep knowledge about or expertise with each one of them. The cloud aims to cut costs and helps the users focus on their core business instead of being impeded by IT obstacles. The main enabling technology for cloud computing is
virtualization In computing, virtualization or virtualisation (sometimes abbreviated v12n, a numeronym) is the act of creating a virtual (rather than actual) version of something, including virtual computer hardware platforms, Data storage device, storage device ...
. Virtualization software separates a physical computing device into one or more "virtual" devices, each of which can be easily used and managed to perform computing tasks. With
operating system–level virtualization OS-level virtualization is an operating system An operating system (OS) is system software System software is software designed to provide a platform for other software. Examples of system software include operating systems like macOS ...
essentially creating a scalable system of multiple independent computing devices, idle computing resources can be allocated and used more efficiently. Virtualization provides the agility required to speed up IT operations and reduces cost by increasing infrastructure utilization. Autonomic computing automates the process through which the user can provision resources on-demand. By minimizing user involvement, automation speeds up the process, reduces labor costs and reduces the possibility of human errors. Cloud computing uses concepts from utility computing to provide
metric METRIC (Mapping EvapoTranspiration at high Resolution with Internalized Calibration) is a computer model Computer simulation is the process of mathematical modelling, performed on a computer, which is designed to predict the behaviour of or th ...
s for the services used. Cloud computing attempts to address QoS (quality of service) and
reliability Reliability, reliable, or unreliable may refer to: Science, technology, and mathematics Computing * Data reliability (disambiguation), Data reliability, a property of some disk arrays in computer storage * High availability * Reliability (computer ...
problems of other
grid computing Grid computing is the use of widely distributed computer A computer is a machine that can be programmed to Execution (computing), carry out sequences of arithmetic or logical operations automatically. Modern computers can perform generic s ...
models. Cloud computing shares characteristics with: *
Client–server model Client-server model is a distributed application Distributed computing is a field of computer science that studies distributed systems. A ''distributed system'' is a system whose components are located on different computer network, networked ...
—''Client–server computing'' refers broadly to any
distributed application Distributed computing is a field of computer science that studies distributed systems. A ''distributed system'' is a system whose components are located on different computer network, networked computers, which communicate and coordinate their ac ...
that distinguishes between service providers (servers) and service requestors (clients). *
Computer bureau A computer bureau is a service bureau providing computer services. Computer bureaus developed during the early 1960s, following the development of time-sharing operating systems. These allowed the services of a single large and expensive mainfra ...
—A
service bureau A service bureau is a company that provides business services for a fee. The term has been extensively used to describe technology-based services to financial services companies, particularly banks. Service bureaus are a significant sector within ...
providing computer services, particularly from the 1960s to 1980s. *
Grid computing Grid computing is the use of widely distributed computer A computer is a machine that can be programmed to Execution (computing), carry out sequences of arithmetic or logical operations automatically. Modern computers can perform generic s ...
—A form of distributed and parallel computing, whereby a 'super and virtual computer' is composed of a
cluster Consortium Linking Universities of Science and Technology for Education and Research (CLUSTER) is a collection of twelve Europe Europe is a continent A continent is one of several large landmasses. Generally identified by convention ...
of networked, loosely coupled computers acting in concert to perform very large tasks. *
Fog computing Fog computing or fog networking, also known as fogging, is an architecture that uses edge devices to carry out a substantial amount of computation, storage, and communication locally and routed over the Internet backbone. Concept Fog computing, ...
—Distributed computing paradigm that provides data, compute, storage and application services closer to the client or near-user edge devices, such as network routers. Furthermore, fog computing handles data at the network level, on smart devices and on the end-user client-side (e.g. mobile devices), instead of sending data to a remote location for processing. *
Mainframe computer A mainframe computer, informally called a mainframe or big iron, is a computer A computer is a machine that can be programmed to carry out sequences of arithmetic or logical operations automatically. Modern computers can perform gener ...
—Powerful computers used mainly by large organizations for critical applications, typically bulk data processing such as
census A census is the procedure of systematically calculating, acquiring and recording information Information is processed, organised and structured data Data (; ) are individual facts, statistics, or items of information, often numeric. In ...

census
; industry and consumer statistics; police and secret intelligence services;
enterprise resource planning Enterprise resource planning (ERP) is the integrated management of main business processes, often in real time and mediated by software and technology. ERP is usually referred to as a category of business management software—typically a su ...
; and financial
transaction processing Transaction processing is information processing in computer science Computer science deals with the theoretical foundations of information, algorithms and the architectures of its computation as well as practical techniques for their app ...
. *
Utility computing Utility computing or The Computer Utility is a service provisioning model in which a service provider makes computing resources and infrastructure management available to the customer as needed, and charges them for specific usage rather than a f ...
—The "packaging of computing resources, such as computation and storage, as a metered service similar to a traditional public utility, such as electricity." *
Peer-to-peer Peer-to-peer (P2P) computing or networking is a distributed application Distributed computing is a field of computer science that studies distributed systems. A ''distributed system'' is a system whose components are located on different co ...

Peer-to-peer
—A distributed architecture without the need for central coordination. Participants are both suppliers and consumers of resources (in contrast to the traditional client-server model). *
Green computing Green computing, green ICT as per International Federation of Global & Green ICT "IFGICT", green IT, or ICT sustainability, is the study and practice of environmentally sustainable computing or IT. The goals of green computing are similar to gre ...
—Study and practice of
environmentally sustainable Sustainability is the capacity to endure in a relatively ongoing way across various domains of life. In the 21st century The 21st (twenty-first) century is the current century in the '' Anno Domini'' era or Common Era, in accordance with ...
computing or IT. * Cloud sandbox—A live, isolated computer environment in which a program, code or file can run without affecting the application in which it runs.


Characteristics

Cloud computing exhibits the following key characteristics: * Agility for organizations may be improved, as cloud computing may increase users' flexibility with re-provisioning, adding, or expanding technological infrastructure resources. * Cost reductions are claimed by cloud providers. A public-cloud delivery model converts
capital expenditure Capital expenditure or capital expense (capex or CAPEX) is the money an organization or corporate entity spends to buy, maintain, or improve its fixed assets, such as buildings, vehicles, equipment, or land. It is considered a capital expenditure ...
s (e.g., buying servers) to
operational expenditure An operational definition specifies concrete, replicable procedures that reliably produce a differentiated, measurable outcome. For example, an operational definition of fear often includes measurable physiologic responses such as tachycardia, galva ...
. This purportedly lowers
barriers to entry In theories of competition Competition arises whenever two or more parties strive for a common goal A goal is an idea of the future or desired result that a person or a group of people envision, Planning, plan and commit to achieve. Peop ...
, as infrastructure is typically provided by a third party and need not be purchased for one-time or infrequent intensive computing tasks. Pricing on a utility computing basis is "fine-grained", with usage-based billing options. As well, less in-house IT skills are required for implementation of projects that use cloud computing. The e-FISCAL project's state-of-the-art repository contains several articles looking into cost aspects in more detail, most of them concluding that costs savings depend on the type of activities supported and the type of infrastructure available in-house. * Device and location independence enable users to access systems using a web browser regardless of their location or what device they use (e.g., PC, mobile phone). As infrastructure is off-site (typically provided by a third-party) and accessed via the Internet, users can connect to it from anywhere. *
Maintenance Maintenance may refer to: Biological science * Maintenance of an organism * Maintenance respiration Non-technical maintenance * Alimony, also called ''maintenance'' in British English * Champerty and maintenance, two related legal doctrines ...
of cloud environment is easier because the data is hosted on an outside server maintained by a provider without the need to invest in data center hardware. IT maintenance of cloud computing is managed and updated by the cloud provider's IT maintenance team that reduces cloud computing costs compared with the on-premises data centers. *
Multitenancy The term "software multitenancy" refers to a software architecture in which a single instance (computer science), instance of Computer software, software runs on a server and serves multiple tenants. Systems designed in such manner are often called ...
enables sharing of resources and costs across a large pool of users thus allowing for: ** centralization of infrastructure in locations with lower costs (such as real estate, electricity, etc.) ** peak-load capacity increases (users need not engineer and pay for the resources and equipment to meet their highest possible load-levels) ** utilisation and efficiency improvements for systems that are often only 10–20% utilised. *
Performance A performance is an act of staging or presenting a play, concert, or other form of entertainment. It is also defined as the action or process of carrying out or accomplishing an action, task, or function. Management science In the work place ...
is monitored by IT experts from the service provider, and consistent and loosely coupled architectures are constructed using
web services The term Web service (WS) is either: * a service offered by an electronic device to another electronic device, communicating with each other via the World Wide Web The World Wide Web (WWW), commonly known as the Web, is an information ...
as the system interface. *
Productivity Productivity is the efficiency Efficiency is the (often measurable) ability to avoid wasting materials, energy, efforts, money, and time in doing something or in producing a desired result. In a more general sense, it is the ability to do th ...
may be increased when multiple users can work on the same data simultaneously, rather than waiting for it to be saved and emailed. Time may be saved as information does not need to be re-entered when fields are matched, nor do users need to install application software upgrades to their computer. * Availability improves with the use of multiple redundant sites, which makes well-designed cloud computing suitable for
business continuity Business continuity planning life cycle Business continuity may be defined as "the capability of an organisation to continue the delivery of products or services at pre-defined acceptable levels following a disruptive incident”, and business conti ...
and
disaster recovery Disaster recovery involves a set of policies, tools and procedures to enable the recovery or continuation of vital technology infrastructure and systems following a natural Nature, in the broadest sense, is the natural, physical, material ...
. * Scalability and
elasticity Elasticity often refers to: *Elasticity (physics), continuum mechanics of bodies that deform reversibly under stress Elasticity may also refer to: Information technology * Elasticity (data store), the flexibility of the data model and the clu ...
via dynamic ("on-demand")
provisioning In telecommunication Telecommunication is the transmission of information Information can be thought of as the resolution of uncertainty; it answers the question of "What an entity is" and thus defines both its essence and the nature of ...
of resources on a fine-grained, self-service basis in near real-time (Note, the VM startup time varies by VM type, location, OS and cloud providers), without users having to engineer for peak loads. This gives the ability to scale up when the usage need increases or down if resources are not being used. The time-efficient benefit of cloud scalability also means faster time to market, more business flexibility, and adaptability, as adding new resources doesn’t take as much time as it used to. Emerging approaches for managing elasticity include the use of machine learning techniques to propose efficient elasticity models. *
Security Security is freedom from, or resilience against, potential Potential generally refers to a currently unrealized ability. The term is used in a wide variety of fields, from physics Physics is the natural science that studies matter, its El ...
can improve due to centralization of data, increased security-focused resources, etc., but concerns can persist about loss of control over certain sensitive data, and the lack of security for stored
kernel Kernel may refer to: Computing * Kernel (operating system), the central component of most operating systems * Kernel (image processing), a matrix used for image convolution * Compute kernel, in GPGPU programming * Kernel method, in machine learnin ...
s. Security is often as good as or better than other traditional systems, in part because service providers are able to devote resources to solving security issues that many customers cannot afford to tackle or which they lack the technical skills to address. However, the complexity of security is greatly increased when data is distributed over a wider area or over a greater number of devices, as well as in multi-tenant systems shared by unrelated users. In addition, user access to security
audit log An audit trail (also called audit log) is a security-relevant chronological record, set of records, and/or destination and source of records that provide documentary evidence of the sequence of activities that have affected at any time a specific o ...
s may be difficult or impossible. Private cloud installations are in part motivated by users' desire to retain control over the infrastructure and avoid losing control of information security. The
National Institute of Standards and Technology The National Institute of Standards and Technology (NIST) is a physical sciences Physical science is a branch of natural science that studies abiotic component, non-living systems, in contrast to life science. It in turn has many branches, e ...
's definition of cloud computing identifies "five essential characteristics":


Service models

Though
service-oriented architecture In software engineering Software engineering is the systematic application of engineering approaches to the software development, development of software. A software engineer is a person who applies the principles of software engineering to desi ...
advocates "Everything as a service" (with the acronyms EaaS or XaaS, or simply aas), cloud-computing providers offer their "services" according to different models, of which the three standard models per
NIST The National Institute of Standards and Technology (NIST) is a physical sciences Physical science is a branch of natural science that studies abiotic component, non-living systems, in contrast to life science. It in turn has many branches, e ...

NIST
are Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS). These models offer increasing abstraction; they are thus often portrayed as ''layers'' in a stack: infrastructure-, platform- and software-as-a-service, but these need not be related. For example, one can provide SaaS implemented on physical machines (bare metal), without using underlying PaaS or IaaS layers, and conversely one can run a program on IaaS and access it directly, without wrapping it as SaaS.


Infrastructure as a service (IaaS)

"Infrastructure as a service" (IaaS) refers to online services that provide high-level
APIs Apis or APIS may refer to: *Apis (deity) In ancient Egyptian religion Ancient Egyptian religion was a complex system of polytheistic beliefs and rituals that formed an integral part of ancient Egypt Ancient Egypt was a civilization ...

APIs
used to abstract various low-level details of underlying network infrastructure like physical computing resources, location, data partitioning, scaling, security, backup, etc. A
hypervisor A hypervisor (or virtual machine monitor, VMM, virtualizer) is similar to an emulator In computing, an emulator is Computer hardware, hardware or software that enables one computer system (called the ''host'') to behave like another compute ...
runs the virtual machines as guests. Pools of hypervisors within the cloud operational system can support large numbers of virtual machines and the ability to scale services up and down according to customers' varying requirements. Linux containers run in isolated partitions of a single
Linux kernel The Linux kernel is a free and open-source Free and open-source software (FOSS) is software that is both free software and open-source software where anyone is free software license, freely licensed to use, copy, study, and change the softwar ...
running directly on the physical hardware. Linux
cgroups cgroups (abbreviated from control groups) is a Linux kernel The Linux kernel is a free and open-source, Monolithic kernel, monolithic, Modular design, modular, Computer multitasking, multitasking, Unix-like operating system kernel (operating s ...
and namespaces are the underlying Linux kernel technologies used to isolate, secure and manage the containers. Containerisation offers higher performance than virtualization because there is no hypervisor overhead. IaaS clouds often offer additional resources such as a virtual-machine disk-image library, raw
block storage In computing (specifically data transmission and computer storage, data storage), a block, sometimes called a physical record, is a sequence of bytes or bits, usually containing some whole number of record (computer science), records, having a ma ...
, file or
object storageObject storage (also known as object-based storage) is a computer data storage architecture that manages data as objects, as opposed to other storage architectures like file systems which manages data as a file hierarchy, and block storage which mana ...
, firewalls, load balancers,
IP address An Internet Protocol address (IP address) is a numerical label such as that is connected to a computer network A computer network is a set of s sharing resources located on or provided by . The computers use common s over to communi ...
es, (VLANs), and software bundles. The
NIST The National Institute of Standards and Technology (NIST) is a physical sciences Physical science is a branch of natural science that studies abiotic component, non-living systems, in contrast to life science. It in turn has many branches, e ...

NIST
's definition of cloud computing describes IaaS as "where the consumer is able to deploy and run arbitrary software, which can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, and deployed applications; and possibly limited control of select networking components (e.g., host firewalls)." IaaS-cloud providers supply these resources on-demand from their large pools of equipment installed in
data centers A data center (American English American English (AmE, AE, AmEng, USEng, en-US), sometimes called United States English or U.S. English, is the set of varieties of the English language native to the United States. Currently, American Eng ...
. For wide-area connectivity, customers can use either the Internet or
carrier cloud In cloud computing Cloud computing is the on-demand availability of computer system resources, especially data storage (cloud storage) and computing power, without direct active management by the user. The term is generally used to describe ...
s (dedicated
virtual private network A virtual private network (VPN) extends a private network In IP network The Internet protocol suite is the Conceptual model (computer science), conceptual model and set of communications protocols used in the Internet and similar comput ...
s). To deploy their applications, cloud users install operating-system images and their application software on the cloud infrastructure. In this model, the cloud user patches and maintains the operating systems and the application software. Cloud providers typically bill IaaS services on a utility computing basis: cost reflects the amount of resources allocated and consumed.


Platform as a service (PaaS)

The
NIST The National Institute of Standards and Technology (NIST) is a physical sciences Physical science is a branch of natural science that studies abiotic component, non-living systems, in contrast to life science. It in turn has many branches, e ...

NIST
's definition of cloud computing defines Platform as a Service as: PaaS vendors offer a development environment to application developers. The provider typically develops toolkit and standards for development and channels for distribution and payment. In the PaaS models, cloud providers deliver a
computing platform A computing platform or digital platform is an environment in which a piece of software is executed. It may be the Computer hardware, hardware or the operating system (OS), even a web browser and associated application programming interfaces, or o ...
, typically including operating system, programming-language execution environment, database, and web server. Application developers develop and run their software on a cloud platform instead of directly buying and managing the underlying hardware and software layers. With some PaaS, the underlying computer and storage resources scale automatically to match application demand so that the cloud user does not have to allocate resources manually. Some integration and data management providers also use specialized applications of PaaS as delivery models for data. Examples include iPaaS (Integration Platform as a Service) and dPaaS (Data Platform as a Service). iPaaS enables customers to develop, execute and govern integration flows. Under the iPaaS integration model, customers drive the development and deployment of integrations without installing or managing any hardware or middleware. dPaaS delivers integration—and data-management—products as a fully managed service. Under the dPaaS model, the PaaS provider, not the customer, manages the development and execution of programs by building data applications for the customer. dPaaS users access data through data-visualization tools.


Software as a service (SaaS)

The
NIST The National Institute of Standards and Technology (NIST) is a physical sciences Physical science is a branch of natural science that studies abiotic component, non-living systems, in contrast to life science. It in turn has many branches, e ...

NIST
's definition of cloud computing defines Software as a Service as: In the software as a service (SaaS) model, users gain access to application software and
databases A database is an organized collection of data Data are units of information Information can be thought of as the resolution of uncertainty; it answers the question of "What an entity is" and thus defines both its essence and the nature ...
. Cloud providers manage the infrastructure and platforms that run the applications. SaaS is sometimes referred to as "on-demand software" and is usually priced on a pay-per-use basis or using a subscription fee. In the SaaS model, cloud providers install and operate application software in the cloud and cloud users access the software from cloud clients. Cloud users do not manage the cloud infrastructure and platform where the application runs. This eliminates the need to install and run the application on the cloud user's own computers, which simplifies maintenance and support. Cloud applications differ from other applications in their scalability—which can be achieved by cloning tasks onto multiple
virtual machines In computing, a virtual machine (VM) is the virtualization In computing, virtualization or virtualisation (sometimes abbreviated v12n, a numeronym) is the act of creating a virtual (rather than actual) version of something, including virtual com ...
at run-time to meet changing work demand.
Load balancer In computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes and development of both computer hardware , hardware and softwa ...
s distribute the work over the set of virtual machines. This process is transparent to the cloud user, who sees only a single access-point. To accommodate a large number of cloud users, cloud applications can be ''multitenant'', meaning that any machine may serve more than one cloud-user organization. The pricing model for SaaS applications is typically a monthly or yearly flat fee per user, so prices become scalable and adjustable if users are added or removed at any point. It may also be free. Proponents claim that SaaS gives a business the potential to reduce IT operational costs by outsourcing hardware and software maintenance and support to the cloud provider. This enables the business to reallocate IT operations costs away from hardware/software spending and from personnel expenses, towards meeting other goals. In addition, with applications hosted centrally, updates can be released without the need for users to install new software. One drawback of SaaS comes with storing the users' data on the cloud provider's server. As a result, there could be unauthorized access to the data. Examples of applications offered as SaaS are cloud gaming, games and productivity software like Google Docs and Word Online. SaaS applications may be integrated with
cloud storage Cloud storage is a model of computer data storage in which the digital data is stored in logical Pool (computer science), pools, said to be on "the cloud". The storage virtualization, physical storage spans multiple Server (computing), servers (so ...
or File hosting services, which is the case with Google Docs being integrated with Google Drive and Word Online being integrated with Onedrive.


Mobile "backend" as a service (MBaaS)

In the mobile "backend" as a service (m) model, also known as backend as a service (BaaS), web app and mobile app developers are provided with a way to link their applications to
cloud storage Cloud storage is a model of computer data storage in which the digital data is stored in logical Pool (computer science), pools, said to be on "the cloud". The storage virtualization, physical storage spans multiple Server (computing), servers (so ...
and cloud computing services with application programming interfaces (APIs) exposed to their applications and custom software development kits (SDKs). Services include user management, Push technology, push notifications, integration with social networking services and more. This is a relatively recent model in cloud computing, with most BaaS Startup company, startups dating from 2011 or later but trends indicate that these services are gaining significant mainstream traction with enterprise consumers.


Serverless computing or Function-as-a-Service (FaaS)

Serverless computing is a cloud computing code execution (computing), execution model in which the cloud provider fully manages starting and stopping
virtual machines In computing, a virtual machine (VM) is the virtualization In computing, virtualization or virtualisation (sometimes abbreviated v12n, a numeronym) is the act of creating a virtual (rather than actual) version of something, including virtual com ...
as necessary to serve requests, and requests are billed by an abstract measure of the resources required to satisfy the request, rather than per virtual machine, per hour. Despite the name, it does not actually involve running code without servers. Serverless computing is so named because the business or person that owns the system does not have to purchase, rent or provide servers or virtual machines for the back-end database, back-end code to run on. Function as a service (FaaS) is a service-hosted remote procedure call that leverages serverless computing to enable the deployment of individual functions in the cloud that run in response to events. FaaS is considered by some to come under the umbrella of ''serverless computing'', while some others use the terms interchangeably.


Deployment models


Private cloud

Private cloud is cloud infrastructure operated solely for a single organization, whether managed internally or by a third party, and hosted either internally or externally. Undertaking a private cloud project requires significant engagement to virtualize the business environment, and requires the organization to reevaluate decisions about existing resources. It can improve business, but every step in the project raises security issues that must be addressed to prevent serious vulnerabilities. Self-run data centers are generally capital intensive. They have a significant physical footprint, requiring allocations of space, hardware, and environmental controls. These assets have to be refreshed periodically, resulting in additional capital expenditures. They have attracted criticism because users "still have to buy, build, and manage them" and thus do not benefit from less hands-on management, essentially "[lacking] the economic model that makes cloud computing such an intriguing concept".


Public cloud

Cloud services are considered "public" when they are delivered over the public Internet, and they may be offered as a paid subscription, or free of charge. Architecturally, there are few differences between public- and private-cloud services, but security concerns increase substantially when services (applications, storage, and other resources) are shared by multiple customers. Most public-cloud providers offer direct-connection services that allow customers to securely link their legacy data centers to their cloud-resident applications. Several factors like the functionality of the solutions, Costing, cost, integrational and organizational aspects as well as Security, safety & security are influencing the decision of enterprises and organizations to choose a public cloud or On-premises software, on-premises solution.


Hybrid cloud

Hybrid cloud is a composition of a public cloud and a private environment, such as a private cloud or on-premises resources, that remain distinct entities but are bound together, offering the benefits of multiple deployment models. Hybrid cloud can also mean the ability to connect collocation, managed and/or dedicated services with cloud resources. Gartner defines a hybrid cloud service as a cloud computing service that is composed of some combination of private, public and community cloud services, from different service providers. A hybrid cloud service crosses isolation and provider boundaries so that it can't be simply put in one category of private, public, or community cloud service. It allows one to extend either the capacity or the capability of a cloud service, by aggregation, integration or customization with another cloud service. Varied use cases for hybrid cloud composition exist. For example, an organization may store sensitive client data in house on a private cloud application, but interconnect that application to a business intelligence application provided on a public cloud as a software service. This example of hybrid cloud extends the capabilities of the enterprise to deliver a specific business service through the addition of externally available public cloud services. Hybrid cloud adoption depends on a number of factors such as data security and compliance requirements, level of control needed over data, and the applications an organization uses. Another example of hybrid cloud is one where Information technology, IT organizations use public cloud computing resources to meet temporary capacity needs that can not be met by the private cloud. This capability enables hybrid clouds to employ cloud bursting for scaling across clouds. Cloud bursting is an application deployment model in which an application runs in a private cloud or data center and "bursts" to a public cloud when the demand for computing capacity increases. A primary advantage of cloud bursting and a hybrid cloud model is that an organization pays for extra compute resources only when they are needed. Cloud bursting enables data centers to create an in-house IT infrastructure that supports average workloads, and use cloud resources from public or private clouds, during spikes in processing demands. The specialized model of hybrid cloud, which is built atop heterogeneous hardware, is called "Cross-platform Hybrid Cloud". A cross-platform hybrid cloud is usually powered by different CPU architectures, for example, x86-64 and ARM, underneath. Users can transparently deploy and scale applications without knowledge of the cloud's hardware diversity. This kind of cloud emerges from the rise of ARM-based system-on-chip for server-class computing. Hybrid cloud infrastructure essentially serves to eliminate limitations inherent to the multi-access relay characteristics of private cloud networking. The advantages include enhanced runtime flexibility and adaptive memory processing unique to virtualized interface models.


Others


Community cloud

Community cloud shares infrastructure between several organizations from a specific community with common concerns (security, compliance, jurisdiction, etc.), whether managed internally or by a third-party, and either hosted internally or externally. The costs are spread over fewer users than a public cloud (but more than a private cloud), so only some of the cost savings potential of cloud computing are realized.


Distributed cloud

A cloud computing platform can be assembled from a distributed set of machines in different locations, connected to a single network or hub service. It is possible to distinguish between two types of distributed clouds: public-resource computing and volunteer cloud. * Public-resource computing—This type of distributed cloud results from an expansive definition of cloud computing, because they are more akin to distributed computing than cloud computing. Nonetheless, it is considered a sub-class of cloud computing. * Volunteer cloud—Volunteer cloud computing is characterized as the intersection of public-resource computing and cloud computing, where a cloud computing infrastructure is built using volunteered resources. Many challenges arise from this type of infrastructure, because of the volatility of the resources used to build it and the dynamic environment it operates in. It can also be called peer-to-peer clouds, or ad-hoc clouds. An interesting effort in such direction is Cloud@Home, it aims to implement a cloud computing infrastructure using volunteered resources providing a business-model to incentivize contributions through financial restitution.


Multi cloud

Multi cloud is the use of multiple cloud computing services in a single heterogeneous architecture to reduce reliance on single vendors, increase flexibility through choice, mitigate against disasters, etc. It differs from hybrid cloud in that it refers to multiple cloud services, rather than multiple deployment modes (public, private, legacy).


Poly cloud

Poly cloud refers to the use of multiple public clouds for the purpose of leveraging specific services that each provider offers. It differs from Multi cloud in that it is not designed to increase flexibility or mitigate against failures but is rather used to allow an organization to achieve more that could be done with a single provider.


Big data cloud

The issues of transferring large amounts of data to the cloud as well as data security once the data is in the cloud initially hampered adoption of cloud for big data, but now that much data originates in the cloud and with the advent of bare-metal servers, the cloud has become a solution for use cases including business analytics and geospatial analysis.


HPC cloud

HPC cloud refers to the use of cloud computing services and infrastructure to execute high-performance computing (HPC) applications. These applications consume considerable amount of computing power and memory and are traditionally executed on Computer cluster, clusters of computers. In 2016 a handful of companies, including R-HPC,
Amazon Web Services Amazon Web Services (AWS) is a subsidiary of Amazon Amazon usually refers to: * Amazons In Greek mythology, the Amazons (Ancient Greek: Ἀμαζόνες ''Amazónes'', singular Ἀμαζών ''Amazōn'') are portrayed in a number of an ...
, Univa, Silicon Graphics International, Sabalcore, Gomput, and Penguin Computing offered a high performance computing cloud. The Penguin On Demand (POD) cloud was one of the first non-virtualized remote HPC services offered on a Prepayment for service, pay-as-you-go basis. Penguin Computing launched its HPC cloud in 2016 as alternative to Amazon's EC2 Elastic Compute Cloud, which uses virtualized computing nodes.


Architecture

Cloud computing architecture, Cloud architecture, the systems architecture of the software systems involved in the delivery of cloud computing, typically involves multiple ''cloud components'' communicating with each other over a loose coupling mechanism such as a messaging queue. Elastic provision implies intelligence in the use of tight or loose coupling as applied to mechanisms such as these and others.


Cloud engineering

Cloud engineering is the application of engineering disciplines of cloud computing. It brings a systematic approach to the high-level concerns of commercialization, standardization and governance in conceiving, developing, operating and maintaining cloud computing systems. It is a multidisciplinary method encompassing contributions from diverse areas such as systems engineering, systems, software engineering, software, web engineering, web, performance engineering, performance, information technology engineering, security engineering, security, platform engineering, platform, Risk analysis (engineering), risk, and Quality control, quality engineering.


Security and privacy

Cloud computing poses privacy concerns because the service provider can access the data that is in the cloud at any time. It could accidentally or deliberately alter or delete information. Many cloud providers can share information with third parties if necessary for purposes of law and order without a warrant. That is permitted in their privacy policies, which users must agree to before they start using cloud services. Solutions to privacy include policy and legislation as well as end-users' choices for how data is stored. Users can encrypt data that is processed or stored within the cloud to prevent unauthorized access. Identity management systems can also provide practical solutions to privacy concerns in cloud computing. These systems distinguish between authorized and unauthorized users and determine the amount of data that is accessible to each entity. The systems work by creating and describing identities, recording activities, and getting rid of unused identities. According to the Cloud Security Alliance, the top three threats in the cloud are ''Insecure Interfaces and APIs'', ''Data Loss & Leakage'', and ''Hardware Failure''—which accounted for 29%, 25% and 10% of all cloud security outages respectively. Together, these form shared technology vulnerabilities. In a cloud provider platform being shared by different users, there may be a possibility that information belonging to different customers resides on the same data server. Additionally, Eugene Schultz, chief technology officer at Emagined Security, said that hackers are spending substantial time and effort looking for ways to penetrate the cloud. "There are some real Achilles' heels in the cloud infrastructure that are making big holes for the bad guys to get into". Because data from hundreds or thousands of companies can be stored on large cloud servers, hackers can theoretically gain control of huge stores of information through a single attack—a process he called "hyperjacking". Some examples of this include the Dropbox security breach, and iCloud 2014 leak. Dropbox had been breached in October 2014, having over 7 million of its users passwords stolen by hackers in an effort to get monetary value from it by Bitcoins (BTC). By having these passwords, they are able to read information privacy, private data as well as have this data be indexed by search engines (making the information public). There is the problem of legal ownership of the data (If a user stores some data in the cloud, can the cloud provider profit from it?). Many Terms of Service agreements are silent on the question of ownership. Physical control of the computer equipment (private cloud) is more secure than having the equipment off-site and under someone else's control (public cloud). This delivers great incentive to public cloud computing service providers to prioritize building and maintaining strong management of secure services. Some small businesses that don't have expertise in Information technology, IT security could find that it's more secure for them to use a public cloud. There is the risk that end users do not understand the issues involved when signing on to a cloud service (persons sometimes don't read the many pages of the terms of service agreement, and just click "Accept" without reading). This is important now that cloud computing is becoming popular and required for some services to work, for example for an intelligent personal assistant (Apple's Siri or Google Now). Fundamentally, private cloud is seen as more secure with higher levels of control for the owner, however public cloud is seen to be more flexible and requires less time and money investment from the user.


Limitations and disadvantages

According to Bruce Schneier, "The downside is that you will have limited customization options. Cloud computing is cheaper because of Economies of scale, economics of scale, and—like any outsourced task—you tend to get what you want. A restaurant with a limited menu is cheaper than a personal chef who can cook anything you want. Fewer options at a much cheaper price: it's a feature, not a bug." He also suggests that "the cloud provider might not meet your legal needs" and that businesses need to weigh the benefits of cloud computing against the risks. In cloud computing, the control of the back end infrastructure is limited to the cloud vendor only. Cloud providers often decide on the management policies, which moderates what the cloud users are able to do with their deployment. Cloud users are also limited to the control and management of their applications, data and services. This includes data caps, which are placed on cloud users by the cloud vendor allocating a certain amount of bandwidth for each customer and are often shared among other cloud users. Privacy and confidentiality are big concerns in some activities. For instance, sworn translators working under the stipulations of an non-disclosure agreement, NDA, might face problems regarding sensitive data that are not encrypted. Due to the use of the internet, confidential information such as employee data and user data can be easily available to third-party organisations and people in Cloud Computing. Cloud computing is beneficial to many enterprises; it lowers costs and allows them to focus on competence instead of on matters of IT and infrastructure. Nevertheless, cloud computing has proven to have some limitations and disadvantages, especially for smaller business operations, particularly regarding security and downtime. Technical outages are inevitable and occur sometimes when cloud service providers (CSPs) become overwhelmed in the process of serving their clients. This may result in temporary business suspension. Since this technology's systems rely on the Internet, an individual cannot access their applications, server, or data from the cloud during an outage.


Emerging trends

Cloud computing is still a subject of research. A driving factor in the evolution of cloud computing has been chief technology officers seeking to minimize risk of internal outages and mitigate the complexity of housing network and computing hardware in-house. They are also looking to share information to workers located in diverse areas in near and real-time, to enable teams to work seamlessly, no matter where they are located. Since the global pandemic of 2020, it is said that cloud technology jumped ahead in popularity due to the level of security of data and the flexibility of working options for all employees, notably remote workers. For example, Zoom grew over 160% in 2020 alone.


Digital forensics in the cloud

The issue of carrying out investigations where the cloud storage devices cannot be physically accessed has generated a number of changes to the way that digital evidence is located and collected. New process models have been developed to formalize collection. In some scenarios existing digital forensics tools can be employed to access cloud storage as networked drives (although this is a slow process generating a large amount of internet traffic). An alternative approach is to deploy a tool that processes in the cloud itself. For organizations using Office 365 with an 'E5' subscription, there is the option to use Microsoft's built-in e-discovery resources, although these do not provide all the functionality that is typically required for a forensic process.


See also

* Block-level storage * :Cloud computing providers * :Cloud platforms * Communication protocol * Communications system * Cloud collaboration * Cloud computing security * Cloud computing comparison * Cloud management * Cloud research * Cloud robotics * Cloud storage * Cloudlet * Computer cluster * Cooperative storage cloud * Dew computing * Data cluster * Directory (computing), Directory * Distributed data store * Distributed database * Distributed computing * Distributed networking * Decentralized computing * Edge computing * Edge device * eScience * File system ** Clustered file system ** Distributed file system ** Distributed file system for cloud *
Fog computing Fog computing or fog networking, also known as fogging, is an architecture that uses edge devices to carry out a substantial amount of computation, storage, and communication locally and routed over the Internet backbone. Concept Fog computing, ...
* Fog robotics *
Grid computing Grid computing is the use of widely distributed computer A computer is a machine that can be programmed to Execution (computing), carry out sequences of arithmetic or logical operations automatically. Modern computers can perform generic s ...
* In-memory database * In-memory processing * Internet of things * Microservices * Mobile cloud computing * Mobile edge computing *
Peer-to-peer Peer-to-peer (P2P) computing or networking is a distributed application Distributed computing is a field of computer science that studies distributed systems. A ''distributed system'' is a system whose components are located on different co ...

Peer-to-peer
* Personal cloud * Robot as a service * Service-oriented architecture * Time-sharing * Ubiquitous computing * Virtual Desktop Infrastructure, VDI * Virtual private cloud * Web computing


References


Further reading

* * * * * Mell, P. (2011, September 31).
The NIST Definition of Cloud Computing
'. Retrieved November 1, 2015, from National Institute of Standards and Technology website


External links

* {{DEFAULTSORT:Cloud Computing Cloud computing, Cloud infrastructure