Cloud Computing

Cloud computing is Internet-based computing, whereby shared servers provide resources, software, and data to computers and other devices on demand, as with the electricity grid. Cloud computing is a natural evolution of the widespread adoption of virtualization, service-oriented architecture and utility computing. Details are abstracted from consumers, who no longer have need for expertise in, or control over, the technology infrastructure "in the cloud" that supports them.

Cloud computing describes a new supplement, consumption, and delivery model for IT services based on the Internet, and it typically involves over-the-Internet provision of dynamically scalable and often virtualized resources.It is a byproduct and consequence of the ease-of-access to remote computing sites provided by the Internet.This frequently takes the form of web-based tools or applications that users can access and use through a web browser as if it were a program installed locally on their own computer.

The National Institute of Standards and Technology (NIST) provides a somewhat more objective and specific definition here.The term "cloud" is used as a metaphor for the Internet, based on the cloud drawing used in the past to represent the telephone network,and later to depict the Internet in computer network diagrams as an abstraction of the underlying infrastructure it represents.Typical cloud computing providers deliver common business applications online that are accessed from another Web service or software like a Web browser, while the software and data are stored on servers.

Most cloud computing infrastructures consist of services delivered through common centers and built on servers. Clouds often appear as single points of access for consumers' computing needs. Commercial offerings are generally expected to meet quality of service (QoS) requirements of customers, and typically include service level agreements (SLAs).The major cloud service providers include Amazon, Rackspace Cloud, Salesforce, Skytap, Microsoft and Google.Some of the larger IT firms that are actively involved in cloud computing are Fujitsu, Dell,Red Hat,Hewlett Packard,IBM,VMware, and NetApp.

Comparisons
Cloud computing derives characteristics from, but should not be confused with:

Autonomic computing — "computer systems capable of self-management"
Client–server model – client–server computing refers broadly to any distributed application that distinguishes between service providers (servers) and service requesters (clients)
Grid computing — "a form of distributed computing and parallel computing, whereby a 'super and virtual computer' is composed of a cluster of networked, loosely coupled computers acting in concert to perform very large tasks"
Mainframe computer — powerful computers used mainly by large organizations for critical applications, typically bulk data-processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.
Utility computing — 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 – distributed architecture without the need for central coordination, with participants being at the same time both suppliers and consumers of resources (in contrast to the traditional client–server model)
Service-oriented computing – Cloud computing provides services related to computing while, in a reciprocal manner, service-oriented computing consists of the computing techniques that operate on software-as-a-service.

Characteristics

The fundamental concept of cloud computing is that the computing is "in the cloud" i.e. that the processing (and the related data) is not in a specified, known or the same place(s). This is in opposition to where the processing takes place in one or more specific servers that are known. All the other concepts mentioned are supplementary or complementary to this concept.

Generally, cloud computing customers do not own the physical infrastructure, instead avoiding capital expenditure by renting usage from a third-party provider. They consume resources as a service and pay only for resources that they use. Many cloud-computing offerings employ the utility computing model, which is analogous to how traditional utility services (such as electricity) are consumed, whereas others bill on a subscription basis. Sharing "perishable and intangible" computing power among multiple tenants can improve utilization rates, as servers are not unnecessarily left idle, which can reduce costs significantly while increasing the speed of application development. A side-effect of this approach is that overall computer usage rises dramatically, as customers do not have to engineer for peak load limits.In addition, "increased high-speed bandwidth" makes it possible to receive the same. The cloud is becoming increasingly associated with small and medium enterprises (SMEs) as in many cases they cannot justify or afford the large capital expenditure of traditional IT. SMEs also typically have less existing infrastructure, less bureaucracy, more flexibility, and smaller capital budgets for purchasing in-house technology. Similarly, SMEs in emerging markets are typically unburdened by established legacy infrastructures, thus reducing the complexity of deploying cloud solutions.

AirSet
AirSet is a privately held consumer cloud storage company based in Berkeley, California, United States, their main product works via a web browser and various mobile platforms

Product
When users registered with AirSet, they each get a Personal Cloud Computer that helps to manage his/her personal life. The personal cloud computer helps individuals keep track of personal calendars and contacts on the web and across different devices (cell phones, PDAs, desktops, etc.). The personal cloud computer also makes it possible for an individual to access his/her files anywhere anytime.

To manage other groups like family, work, and community in ones life, a user can add as many Group Cloud Computers to their AirSet network. A Group Cloud Computer comes with all the apps and features of a Personal Cloud Computer. But it also helps members of a group find out what’s going on in the group, make plans together, and contribute their input to the group.

Once a user sets up more than one cloud computer in their network, all of these cloud computers are networked together. The user can band together with other individual users in a number of groups that are of varying degrees of permanence. When the user leaves one group, he/she may lose membership to that one particular group, but retain all his/her other relationships.

One comment in the AirSet user community forum compared AirSet with other competitors. Creating new groups in Google Apps, Zoho Business, Blackboard, and Moodle follows a pyramid structure. If anyone wants to create a new group, they have to ask the person above them in the hierarchy. AirSet, on the other hand, is more like “an ideal 18th century town. Everyone is queen of her own castle, and people join together in different overlapping groups, needing nobody else's permission. I am the head teacher in the school and I rule the school group. Jeff is the head volunteer fireman and I am a member of his group. And so on. Importantly, groups can come and go. Some of us decide to hold a summer fair. The originator of the idea starts a temporary group. We join. The fair is held. The task is done and the group is disbanded. In this model there is no King, and groups are tools through which people come together for as long as necessary – and groups interact and overlap as needed..

 

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 application programming interfaces, usually web services. This resembles the Unix philosophy of having multiple programs each doing one thing well and working together over universal interfaces. Complexity is controlled and the resulting systems are more manageable than their monolithic counterparts.
The two most significant components of cloud computing architecture are known as the front end and the back end. The front end is the part seen by the client, i.e. the computer user. This includes the client’s network (or computer) and the applications used to access the cloud via a user interface such as a web browser. The back end of the cloud computing architecture is the ‘cloud’ itself, comprising various computers, servers and data storage devices.