What are the different types of cloud computing?
Web-based email services from Google and Yahoo, backup services from Carbonite or MozyHome, customer-resource management applications like Salesforce.com, instant messaging and voice-over-IP services from AOL, Google, Skype, Vonage and others are all cloud-computing services, hidden behind yet another layer of abstraction to make them seem even simpler to end users who want the kind of power sophisticated computing can give them, but don't want to know how it's done.
There are three basic types of cloud computing:
• Infrastructure as a Service - provides grids or clusters or virtualized servers, networks, storage and systems software designed to augment or replace the functions of an entire data center. The highest-profile example is Amazon's Elastic Compute Cloud [EC2] and Simple Storage Service, but IBM and other traditional IT vendors are also offering services, as is telecom-and-more provider Verizon Business.
• Platform as a Service - Provides virtualized servers on which users can run existing applications or develop new ones without having to worry about maintaining the operating systems, server hardware, load balancing or computing capacity. Highest-profile examples include Microsoft's Azure and Salesforce's Force.com.
• Software as a Service - The most widely known and widely used form of cloud computing, SaaS provides all the functions of a sophisticated traditional application, but through a Web browser, not a locally-installed application. SaaS eliminates worries about app servers, storage, application development and related, common concerns of IT. Highest-profile examples are Salesforce.com, Google's Gmail and Apps, instant messaging from AOL, Yahoo and Google, and VoIP from Vonage and Skype.
Why would I want cloud computing?
According to critics, there are nearly as many reasons not to want cloud computing as there are reasons to use it.
The arguments for cloud computing are simple: get sophisticated data-center services on demand, in only the amount you need and can pay for, at service levels you set with the vendor, with capabilities you can add or subtract at will.
However, if someone else owns the computer infrastructure you rely on, you don't have the kind of control over your data and the performance of your applications that you may need, not to mention the ability to audit or change the processes and policies under which even authorized users must work.
A slew of software vendors are rushing into the market to fill this gap with management tools, but that set of products remains quite young.
Complying with HIPAA, Sarbox and other federal regulations - and, more importantly, demonstrating to auditors that you have - is extremely difficult right now with regards to cloud, according to Chris Wolf, virtualization and infrastructure analyst at The Burton Group.
"When you're talking about virtualization, at least there's some commonality in the platform, the hypervisor you're using, if not in the hardware behind it," Wolf says. "Cloud is not a one-size-fits-all solution. You have various flavors of SAAS, Amazon's EC2 and other infrastructure services that are all different in how they treat data at rest [in storage] and in motion [when it's being used in applications or communications]. That's a big problem."
Cloud customers risk losing data by having it locked into proprietary formats, may lose control over data because tools to see who's using it or who can view it as it moves across the network are inadequate, or may lose confidence in it because they don't know when data has been compromised or how, Wolf says.
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