This week we are learning about service models. Cloud services can be obtained as a number of different services, based on the user's needs and requirements. Among additional products, three of those service models are the fundamental ones -  Software as a Service (SaaS), Platform as a Service (PaaS) and Infrastructure as a Service (IaaS).
SaaS allows a user to use a software product without having to deal with anything that comes with owning software - updates, maintenance of hardware, backups, security etc. The SaaS provider simply provides the software to the user and takes care of everything else.
PaaS allows the user to utilize the provider's platform and environment to create applications over the internet, using tools, languages and libraries that are supported by the provider.
IaaS provides virtualized hardware, or a computing infrastructure. This can include virtual server space, bandwidth, network connections and IP addresses. Physical servers and hardware are distributed across several data center which the provider maintains and is responsible for. The user utilizes the virtual components to create his own platform.

This is week 2 of our cloud class and we are learning about cloud models. I know what you're thinking - What?! There are different models? Isn't the cloud already confusing and mysterious enough? It really isn't though. Many people, including friends of mine are still "scared" of the cloud. They don't understand it and try to avoid it. There is some hear-say that data gets lost and weird things happen with it. But "the cloud" is not as mysterious as some people think.
   There are public clouds, which most of us use on a daily basis (you might not even realize it). Do you have Gmail, Yahoo mail or such? Then yes, you are using a cloud and it would be a public cloud model. A public cloud model and essentially is a resource that is made available to the public by a service provider (such as Google, Yahoo or Microsoft) Public cloud services are low in cost and can be either free or pay-per-use.
Then there are private cloud models. Private clouds are limited to certain users, such as employees of an organization. Using private clouds allows an organization to retain more control over its data than they would if they would use a public cloud or third party services.
A hybrid cloud model offers the best of both worlds. It allows an organization to manage some resources within and also has other resources provided externally. So a company may be using a public cloud service to store and share certain data, but maintains private services for sensitive data that has to remain within the organization.