It seems that every decade or so I get the opportunity to write an article on IT déjà vu. This time around, the topic is cloud computing, which is the latest IT buzz word.

My first reaction to the term was confusion. The amorphous "cloud" has been used for decades to symbolize a WAN that connected clients to server-based data centers. Is cloud computing another version of network computing? Yes, but this cloud is not just any WAN; it is a synonym for the Internet. Nothing new here. The Internet has been around for over two decades.

OK, let us look at what form of computing in being provided via the cloud. In this model, all IT applications and facilities (i.e. compute, storage and network) are provided as a service rather than dedicated infrastructure. This is intended to allow any user, independent of client platform, to access IT services without knowledge or concern of their location or form. Sound familiar – it’s a service-oriented architecture (SOA)!

Additionally, cloud computing incorporates almost every computing manifestation within the IT world: distributed, grid, utility, on-demand, open source; Web services; P2P; Web 2.0 and, last but not least, software as a service.

It also accommodates thin, thick and mobile clients, and allows integration of corporate, commercial and service provider cloud-accessed resources. As an example, in this model, storage is a service resource that is accessed via the cloud, not a dedicated user resource.

Cloud computing vendors will invoice their customers on a utility (such as electricity) or a subscription (such as a newspaper) basis.

Evolutionary, but not revolutionary. As early as 1970, IBM championed a concept called "time sharing." Users shared common IT resources and applications on a mainframe computer simultaneously with other users for variable fees that were dependent upon usage and consumed resources.

Minimal CAPEX, low barrier to entry, shared IT infrastructure as well as shared costs, outsourced OPEX, low management overhead and immediate access to a broad range of business and IT applications are all benefits of time sharing. Almost 40 years later, we are back full circle to cloud computing.

Déjà vu, but with a 21st century twist. Virtualization, autonomics, open standards, massive resource scaling, dynamic resource provisioning, mobile broadband access, the IP Internet, Ethernet LANs, computer-based smart clients, NAS, dense low-cost RAID storage, DBMS, ESB, information management, system/network management and security software, etc., did not exist in the age of time sharing.