What is Cloud Computing?History Types of cloud computing.How cloud computing worksService models why cloud computing CharacteristicsDifference between cloud computing and web hostingAdvantages & Disadvantages
“Cloud” is simply a metaphor for the internet. The name comes from the use of a cloud-shaped symbol as an abstraction for the complex infrastructure. It is a technology that uses the internet & central remote servers to maintain data & application. Users simply rent or access the software, paying only for what they use. Cloud computing allows consumers to use applications without installation & access their personal files at any computer with internet access.
The analogy is “ If you need milk,would you buy a cow?”
The concept was born in the 1960 from theideas of pioneers like- J.C.R Lickliden (instrumental in the development of ARPANET
John McCarthy( who coined the term “artificialintelligence”) “computation may someday be organized as a public utility” In 1997 the term “cloud computing” was first used by information system professor Ramnath Chellappa
Public cloud:-A public cloud is one based on the standard cloud computing model, in which a service provider makes resources, such as applications and storage, available to the general public over the Internet. Public cloud services may be free or offered on a pay-per- usage model. Example-Amazon Ec2
Private cloud:- The computing infrastructure is dedicated to a particular organization and not shared with other organizations. Example- VMware, 3D Render Farm used to create 3D content
Hybrid cloud:- Organizations may host critical applications on private clouds and applications with relatively less security concerns on the public cloud. The usage of both private and public clouds together is called hybrid cloud.
Cloud computing consists of following layersBack end layer- the one you see and interact with.example – when you access your e-mail ong-mail.Front end layer – consist of hardware and software architecture that delivers the data you see on the front end.
Software as a service (SaaS)It is a software distribution model. In this modelapplications are made available to customers over anetwork, typically the internet. SaaS describes whenusers ‘rent’ or borrow online software instead of actuallypurchasing and installing it on their own computers.Examples - Google Apps, QuickBooks Online,Salesforce.com
Platform as a service (PaaS)This is a variant of SaaS. You run your own applicationbut you do it on the cloud provider’s infrastructure.While SaaS offers applications for end users PaaS offersa development platform for developers . Developers donot need to worry about the OS , storage or hosting.Developers write the code and PaaS provider providesa very simple method to upload that code and presentit on the internet.Examples of PaaS include: Amazon Elastic Beanstalk,
Infrastructure as a service (IaaS)This is the base structure of the cloud stack. Itserves as a foundation for the other two layers fortheir execution. In IaaS you pay only for theresources you actually consume.Example- Amazon Ec2
Clients would be able to access their application and data from any where at anytimeIt could bring hardware costs down.The companies don’t have to buy a set of software or licenses for every employee.
Cost Effective User centric Powerful Self Healing Flexible Lots of Storage Space Device Diversity
CLOUD COMPUTING WEB HOSTING You pay a fixed amount You pay only for the even if you don’t use the resources you actually resources consume You can easily configure Does not have this your resources based on feature your computing requirements
Inexpensive you do not need to purchase additional hardware your server will have offsite backup in case something goes wrong lots of storage space.Pay only for resources you actually consume you can configure your resources
Security issueInfrastructure No easy migrationEven on fast connection web based applications can sometimesbe slower Requires a constant Internet connection Limited features