Cloud computing originally surfaced around 2007 as simply a means of offloading services from the local intranet to the Internet itself.

Although services such as email have long been put in such an environment, many other services have migrated to cloud-based offerings over the past decade. Services such as scheduling, storage, and infrastructure and thousands of other services have become offerings now available over the Internet and in the cloud.

Organizations started moving services to the cloud for several reasons: lower support costs, reduced internal resource requirements, reduced personnel requirements, and increased flexibility and capacity.

Cloud service providers offer a wide range of cloud services. The most popular types of offerings are based on three models: Platform as a Service (PaaS), Software as a Service (SaaS), and Infrastructure as a Service (IaaS).

Google Docs would be a good example of SaaS because it is available from anywhere and runs over the Internet. Some companies, such as Microsoft, have used this model as a way to allow applications to be used on a subscription basis rather than through the standard licensing model.

IaaS typically refers to a virtual environment in the cloud, in which a business or individual obtains, or provisions, hardware services as needed. Cloud capacity can be provisioned with greater or fewer resources, based on the current needs. Because the infrastructure is cloud based and not owned by the client, the costs typically are lower and paid only as needed. The more resources are used, the more the client will pay. Additionally, companies have realized higher reliability and uptime because cloud vendors provide dedicated environments.

The third cloud computing model is PaaS. This model lives between IaaS and SaaS. With PaaS, the client not only rents access to a virtual infrastructure but also access to certain preinstalled software components. For example, an IaaS offering may provide a collection of virtual machines and storage nodes. The client must install everything. With PaaS, the client would rent access to virtual machines with operating systems, databases, and web servers already installed and configured and any other system-wide software as necessary.

In cloud environments, there are some security issues that can arise above and beyond what is observed with traditional, on-premises environments.

• Availability—Because the environment is offsite and accessed by an Internet connection, any Internet outages would affect accessibility of services.

• Reliability—Again, because the service is in another’s hands, subscribers may find themselves at the whims of the vendor. However, cloud service providers invest heavily to ensure minimum uptime guarantees.

• Loss of control—When services and other items are hosted internally, the company is in control of the stability of its environment. Once these services are moved offsite, control of resources is decreased because it is now handled by another party.

Although there are concerns and potential drawbacks to migrating to cloud computing, a growing number of organizations have already determined that the benefits outweigh the risks. Cloud computing is a reality in most of today’s organizations. It is expected to continue to increase in popularity as computing services move closer and closer to commodity service offerings.