Application Development in the "Cloud"

From an article on GigaOM written by Geva Perry (chief marketing officer at GigaSpace Technologies):

...Although it is difficult to come up with a precise and comprehensive definition of cloud computing, at the heart of it is the idea that applications run somewhere on the “cloud” (whether an internal corporate network or the public Internet) – we don’t know or care where. But as end users, that’s not big news: We’ve been using web applications for years without any concern as to where the applications actually run.

The big news is for application developers and IT operations. Done right, cloud computing allows them to develop, deploy and run applications that can easily grow capacity (scalability), work fast (performance), and never — or at least rarely — fail (reliability), all without any concern as to the nature and location of the underlying infrastructure.

Taken to the next step, this implies that cloud computing infrastructures, and specifically their middleware and application platforms, should ideally have these characteristics:

• Self-healing: In case of failure, there will be a hot backup instance of the application ready to take over without disruption (known as failover)...
• SLA-driven: The system is dynamically managed by service-level agreements that define policies such as how quickly responses to requests need to be delivered...
• Multi-tenancy: The system is built in a way that allows several customers to share infrastructure, without the customers being aware of it and without compromising the privacy and security of each customer’s data.
• Service-oriented: The system allows composing applications out of discrete services that are loosely coupled (independent of each other)...
• Linearly Scalable: Perhaps the biggest challenge. The system will be predictable and efficient in growing the application. If one server can process 1,000 transactions per second, two servers should be able to process 2,000 transactions per second, and so forth.
• Data, Data, Data: The key to many of these aspects is management of the data: its distribution, partitioning, security and synchronization...