It seems as if almost everything is being called a cloud these days. One of the more recent ideas is the “Personal Cloud.”
First, let’s say that Personal Clouds are cloud solutions used by people, not “things.” Intuitively, a personal cloud should be a cloud that is used by (or belongs to) an individual acting on their own behalf.
According to Gartner:
“Personal cloud is the individual’s collection of digital content, services and apps which are seamlessly accessible across any device. The personal cloud is not a tangible entity, but rather the realization of four different types of experience in which users store, synchronize, stream and share content on a contextual basis, moving from one platform, screen and location to another. Founded on interconnected services and applications, it both reflects and sets consumer’s expectations for how next-generation computing services will work.”
Wikipedia references the Gartner definition (although it does not seem to copy it exactly) and states that there are four primary types of personal cloud in use today: online clouds, NAS device clouds, server device clouds, and home-made clouds.
I don’t think of my LinkedIn account as a personal cloud. To me it is one of multiple cloud-based services that I subscribe to and can access from various devices. Similarly, I do not think of a disk attached to my home network as a personal cloud (although it can be described as providing a data storage service).
On the other hand, the set (collection) of cloud services (apps, storage, and communications services) that I have on my iPhone, which appears to me as a personalized computing system, could be called a personal cloud. I doubt there’s anyone else that has my specific collection of apps!
What would the basic characteristics of a Personal Cloud be? In theory, if a personal cloud is truly meant to be a cloud, then it ought to include the basic cloud characteristics (see ISO/IEC 17788/ITU Y.3500):
- Broad network access: Using Internet-compatible access devices should satisfy this requirement. An app that is restricted to one type of device or which does significant processing on the user device may not strictly meet the criteria, however;
- Measured service: Usage should be monitored, controlled, reported and billed in order to optimize and validate the delivered service and to facilitate paying only for resource use. For personal clouds to meet this requirement each accessible service would need to include usage tracking;
- Multi-tenancy: This is a cloud feature in which physical or virtual resources are allocated so that multiple tenants (which could be anything from a person to a corporation) and their computations and data are isolated from and inaccessible to one another. personal clouds should be able to meet this requirement if the underlying cloud services do;
- On-demand self-service: A personal cloud user should have the ability to add or delete services, when they need them, without requiring additional human interactions or overhead. If a personal cloud is self-provisioned (e.g., a home-made cloud), then this characteristic may not apply;
- Rapid elasticity and scalability: This is a feature that allows physical or virtual resources to be rapidly and elastically adjusted, in some cases automatically, to quickly increase or decrease resources. A personal cloud, such as a home-made cloud, may impose limits on this feature but those based on public clouds would be elastic;
- Resource pooling: A personal cloud should, by definition, not be serving more than one individual. However, the underlying physical or virtual resources for each service could be aggregated.
Using the Gartner definition as a basis, I would add the following requirements for a personal cloud:
- Multiple application services from one or more underlying public or private clouds should be supported as a consistent package;
- The collection of services should include content storage, synchronization among apps and people, data streaming and content sharing on a contextual basis; and
- All personal cloud services should be available on any device.
Several broad categories of personal cloud solution could be defined:
- A cloud solution that is implemented by the individual (= an organization of 1?), such as a home-made cloud consisting of a personal storage device that is accessible both locally and remotely over the Internet (this would also be a private cloud);
- A personal account on a public cloud that is isolated from everyone else (e.g., cloud-based storage such as Dropbox); and
- A virtual cloud solution consisting of accounts on multiple clouds, potentially with common features such as access controls and user interfaces. An Apple iPhone with access to multiple cloud apps would appear like this to its owner.
How is a personal cloud different from a user of an enterprise cloud? Is it in the service mix, or is it technically different?
The term “personal” could simply identify a specific cloud role (=the individual user of personal services). This leads to the idea of Role-based Cloud Computing, in which a personal cloud is simply the window for the “person” role. Many role types could be defined: a consumer (buyer) role for shopping; an employee role for company functions and data; and, a personal role for inter-personal communications. For example, a BYOD (bring your own device) device would typically support two cloud roles: the personal role, and the employee role.
Cloud computing is still a fertile ground for innovation at many levels. Hopefully, there will soon be a stable foundation on which to base the development of personal clouds.
