Slideshow: Amazon's Case For Enterprise Cloud Computing
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"First, I'd like to talk a little bit about cloud computing and try to define what we mean… because people use the term to mean many different things. Maybe the two most well known examples of cloud computing represent the opposite spectrums of what's meant by cloud computing. One is Salesforce.com, which has been around a very long time, a very successful application on the Internet and a lot of people call that cloud computing. It's an application on the Internet. You don't run it on your computer; rather you access the application on the web. Is that cloud computing? Or... is it Amazon EC2? The term cloud computing was popularized, came into popular existence with the invention and release of Amazon EC2. And... again it stands in stark contrast to Salesforce.com. It's not an application at all. It's a platform upon which you build applications. And it's relatively new. Very different from Salesforce.com. Needless to say, Oracle agrees with Amazon.com. Our definition is identical to theirs."
As Ellison said, the Exalogic machine bears a resemblance to Amazon's EC2 in that it runs virtualized applications on an x86 server cluster, and the hardware resources serving the application can be made "elastic," or more servers assigned on demand as application's load increases. The appliance isn't as elastic as EC2 but it can expand out to eight racks of servers, if the user chooses, according to Oracle's specs.
But after that comparison, the resemblance to Amazon EC2 ends. On EC2, the user may commission a home-grown application or a customized application to run under standard issue Linux or Windows. On ExaLogic, the customer runs an Oracle application that will use the Oracle database under the Oracle WebLogic application server. Instead of customizing the software to his needs, according to the Exalogic presentation by Ellison, the customer will learn that the appliance approach means the software runs better if no one but Oracle touches it.
Ellison continued his definition: "We believe it's a platform. We believe on that platform you run standards-based software, a wide variety of software: databases, application development tools, a variety of guest operating systems running on the virtual machines. It's a comprehensive development and execution environment that can run virtually all of your applications. It must be virtualized. It must be elastic. It clearly includes both hardware and software."
These comments, according to the NIST definition, tend to mix several things together. A cloud where users work with programming languages and development tools is a particular type, platform as a service, one of three defined service models. Amazon is not platform as a service. By its own definition, it strictly adheres to infrastructure as a service only -- elastic hardware resources for whatever software you send them. Applications can be built on EC2 but the user brings his own tools and programming languages to do so.
The core Salesforce.com is also not platform as a service; it is considered the inventor of the SaaS model. Within its core Salesforce.com, Salesforce makes it possible to customize the applications. Salesforce also offers a platform, Force.com, where it makes programming languages and tools available for application development to run on the platform.
The Exalogic appliance so far does not appear to be platform as a service, where users will work with development tools, despite Ellison's definition. It appears to come closest to the software as a service model -- SaaS for inside-the-enterprise users. Ellison didn't mention two features that are key to cloud computing, also integral to Amazon's EC2. One is user on-demand, self-service. Both EC2 and Salesforce.com offer self service. The NIST definition of cloud computing calls it "an essential characteristic" of the cloud. The other was "measured service" or a way to meter individual usage to apply a charge per hour or other time unit. Pay-for-use with the Oracle appliance can most likely be implemented through an additional Oracle product, Oracle Enterprise Manager.