CONTENTSIntroductionTypes of cloud computingCloud clientsWorking of cloud computingBenefits of Cloud ComputingRisks of Cloud Computing
Cloud computing is the use of computing resources(hardware and software) that are delivered as aservice over a network (typically the Internet).The name comes from the use of a cloud-shapedsymbol as an abstraction for the complexinfrastructure it contains in system diagrams.Cloud computing entrusts remote services with ausers data, software and computation.
Types of Cloud ComputingInfrastructure as a service (IaaS)Platform as a service (PaaS)Software as a service (SaaS)Storage as a service (STaaS)Security as a service (SECaaS)Data as a service (DaaS)Business process as a service (BPaaS)Test environment as a service (TEaaS)Desktop as a service (DaaS)API as a service (APIaaS)
SaaS (Software As A Service)Is the most widely known and widely used form of cloud computing. Itprovides all the functions of a sophisticated traditional applicationto many customers and of ten thousands of users, but through aWeb browser, not a “locally -installed” application.Little or no code is running on the Users local computer and theapplications are usually tailored to fulfill specific functions.SaaS eliminates customer worries about application servers, storage,application development and related, common concerns of it.Examples are Salesforce.com, Googles Gmail and Apps, instantmessaging from AOL, Yahoo and Google, and VoIP fromVonage and Skype.
PaaS (Platform as a Service)Delivers virtualized servers on which customers can runexisting applications or develop new ones without having toworry about maintaining the operating systems, server hardware,load balancing or computing capacity.These vendors provide APIs or development platforms tocreate and run applications in the cloud – e.g. using theInternet. Managed Service providers with applicationservices provided to IT departments to monitor systems anddownstream applications such as virus scanning for e-mail arefrequently included in this category.Well known providers would include Microsofts Azure, Salesforces Force.com, Google Maps, ADP Payroll processing,and US Postal Service offerings.
IaaS (Infrastructure as a Service)Delivers utility computing capability, typically as raw virtualservers, on demand that customers configure and manage. HereCloud Computing provides grids or clusters or virtualized servers,networks, storage and systems software, usually (but not always) ina multitenant architecture.IaaS is designed to augment or replace the functions of an entiredata center. This saves cost (time and expense) of capital equipmentdeployment but does not reduce cost of configuration,integration or management and these tasks must be performedremotely.Vendors would include Amazon.com (Elastic Compute Cloud [EC2]and Simple Storage), IBM and other traditional IT vendors.
STORAGE AS A SERVICE(STAAS)Storage as a service (STaaS) is a business model inwhich a large service provider rents space in theirstorage infrastructure on a subscription basis. Theeconomy of scale in the service providersinfrastructure allows them to provide storage muchmore cost effectively than most individuals orcorporations can provide their own storage,when total cost of ownership is considered.Storage as a Service is often used to solve offsitebackup challenges.
BUSINESS PROCESS AS A SERVICE (BPAAS)Business process as a service (BPaaS) pronounced [bē-păss] isan application delivered as a service that is used by businessprocess service-provider personnel, who are performing activitieson behalf of the service recipient. Its a service that combinesthe Business Process Outsourcing (BPO) with theSoftware as aService (SaaS) models. BPaaS is a model for businessesoutsource traditional business services. The difference withBPaaS over BPO is that BPaaS emphases on the end results versusoperational activities. Where typical BPO programs will have theclient focusing on daily operational tasks to deliver the outcome,BPaaS focuses on service level agreements (SLA) and KeyPerformance Indicators (KPI) as the measure of operationalservice and success.
TEST ENVIRONMENT AS A SERVICE (TEAAS)Test Environment as a service (TEaaS,typically pronounced [teæs]), sometimesreferred to as "on-demand test environment,"is a test environment delivery model in whichsoftware and itsassociated data are hosted centrally (typicallyin the (Internet) cloud) and are typicallyaccessed by users using a thin client, normallyusing a web browser over the Internet.
API AS A SERVICE(APLAAS)API as a service is a serviceplatform that enables the creationand hosting of APIs (applicationprogramming interfaces).These APIs normally providemultiple entry points for API callsranging from REST, XML webservices or TCP/IP.
CLOUD CLIENTSUsers access cloud computing using networked client devices, suchas desktop computers, laptops, tablets and smartphones. Some ofthese devices - cloud clients - rely on cloud computing for all or amajority of their applications so as to be essentially useless withoutit. Examples are thin clients and the browser-based Chromebook.Many cloud applications do not require specific software on theclient and instead use a web browser to interact with the cloudapplication. With Ajax and HTML5 these Web user interfaces canachieve a similar or even better look and feel as native applications.Some cloud applications, however, support specific client softwarededicated to these applications (e.g., virtual desktop clients andmost email clients). Some legacy applications (line of businessapplications that until now have been prevalent in thin clientWindows computing) are delivered via a screen-sharing technology.
HOW DOES CLOUD COMPUTING WORK?Cloud computer works by hosting yourinformation on computers „out there‟ „inthe cloud‟. The cloud is basically a batchof computers called data centers orservers that hold your information(files,images,videos,etc) and can belocated anywhere. You‟re working in acloud because you don‟t have to storesoftware or files on your own computer.
BENEFITS OF CLOUD COMPUTINGCloud Computing brings with it many benefits to the enduser. These include:Access to a huge range of applications without havingto download or install anythingApplications can be accessed from any computer,anywhere in the worldUsers can avoid expenditure on hardware andsoftware; only using what they needCompanies can share resources in one placeConsumption is billed as a utility with minimal upfrontcostsScalability via on-demand resources
RISKS OF CLOUD COMPUTINGCloud Computing has many benefits, however there arealso some associated risks with using cloud computing.These include:Users do not physically possess storage of their owndata, which leaves the responsibility and control ofdata storage with the providerUsers could become dependent upon the cloudcomputing providerWith data held externally, business continuity anddisaster recovery are in the hands of the providerData migration issues when changing cloud providerWhat happens if your cloud provider goes out ofbusiness?