What is cloud computing?
Cloud computing is a category of computing solutions in which a technology or service lets users access computing resources on demand, as needed, regardless of whether the resources are physical or virtual, dedicated or shared, and no matter how you access them (through a direct connection, LAN, WAN, or the Internet).
Cloud computing's importance rests in the cloud's potential to save investment costs in infrastructure, save time in application development and deployment, and save resource allocation overhead.
What's the difference between public, private, and hybrid clouds?
A private cloud reproduces the delivery models of a public cloud behind a firewall for the exclusive benefit of an organization and its customers. The self-service management interface is still in place, while the IT infrastructure resources being collected are internal.
A public cloud is an environment that exists outside a company's firewall, such as a service that a third-party vendor offers. It is also referred to as a shared or multitenanted, virtualized infrastructure managed by means of a self-service portal.
In a hybrid cloud environment, external services are leveraged to extend or supplement an internal cloud.
Is cloud computing the same as SaaS, Paas, IaaS?
Cloud-based applications, or Software as a Service, run on distant computers "in the cloud" that are owned and operated by others.
PaaS provides a computing platform and environment that allow you to build applications and services.
IaaS provides the servers, virtual machines, storage capacity, load balancers, and so on.
What can run in the cloud and can applications move between clouds?
Types of apps
Anything can run in a cloud, but that doesn't mean anything should run in a cloud. A cloud is right on target for applications that deal with IT management, big data, development and deployment, capacity (server or storage), and collaboration.
In some cases sensitive customer data should perhaps not be in a public cloud and is sometime prohibited by regulations.
Open standards enable applications to move between different cloud environments. Organizations like IBM and OpenStack are committed to open standards for cloud.