To help understand what makes up the Cloud, Microsoft’s Darryl Chantry in an article entitled Mapping Applications to the Cloud, describes five broad categories that are used by service providers when mapping applications in the Cloud.
Below is a quick overview.
In practical terms, cloud infrastructure refers to the virtual servers that provide the horsepower to support large-scale processes and high-use applications. Cloud infrastructure runs on virtualisation, with large data centres running virtual servers that allow organisations to leverage economies of scale by sharing infrastructure resources, as well as removing the need to buy and maintain expensive hardware.
A cloud platform is the environment in which applications are built, tested, deployed, run, and managed. Generally speaking, cloud platforms provide low-cost and highly-scalable hosting and development environments for web-based applications and cloud services. It is tempting to view cloud platform as a more sophisticated form of web hosting
, but this would be an oversimplification. One of the major disadvantages of cloud platforms is portability. When an application is designed to run on a specific platform, moving it to another platform or hosting environment is not viable.
Any type of data residing in the Cloud is storage. Services that provide database functionality, unstructured data services (digital media files, for example), data synchronisation services, or Network Attached Storage (NAS) services are all forms of cloud storage. Data storage services are often used in a pay-as-you-go model, or a pay-per-GB model.
Fast, low-cost, and nearly infinitely scalable, data storage services offer numerous benefits, including the ability to store and retrieve large amounts of data at any time in any location. However, there are some issues associated with cloud storage. These include reliability, as even top-notch services are prone to occasional failures. Another major concern is transaction support, which needs to be addressed for storage services to become widely used.
A cloud application exists within the Cloud, either partially or fully, and uses cloud services to apply the core features of an application. Implementing cloud applications often requires a fundamental shift in the application-design thought process, as today’s cloud applications are considerably different from traditional application models.
One of the most common types of cloud applications is the Software as a Service (SaaS) application. These applications often remove the need to install and run applications locally, thus reducing costs associated with software maintenance, deployment, management, and support. A hybrid alternative to the SaaS application is the Software plus Services (S+S) model, a cross between traditional application development and SaaS implementation. These use rich client applications that are installed on the client’s PC and operate as an interface into externally hosted services. S+S often includes the ability to sync back to a central service and interact with an application in offline mode.
Core Cloud Services
Core cloud services support such common cloud-based services as identity management, mapping, billing and payment systems, messaging, search, service-to-service integration, workflow, and business process management, among many others. These core cloud services may be consumed indirectly through system-to-system integration or by an individual.
The common perception is that the evolution of core cloud services will develop similarly to the telecommunications industry, with services falling under Business Support Systems (BSS) or Operational Support Systems (OSS). BSS services include tasks such as taking orders, bill processing, and payment collection, while OSS services manage items such as service monitoring, service provisioning, and service configuration.