What is Cloud Computing?

Everyone talks about it, but what does cloud mean to you and your business? This article explains that cloud is foremost an IT solution architecture, which comes in flavors of public, private, and hybrid cloud. It also describes IaaS, PaaS, and SaaS, as the 3 main flavors of cloud services. Cloud computing has its benefits and challenges, and these will be addressed in an upcoming article.

Cloud Architecture

Cloud computing is an IT solution architecture that came to prominence since 2000 and has now become a real buzz. Cloud computing evolved from enterprise computing, characterized by reusable and mashed-up web services in a Service Oriented Architecture (SOA). In comparison to enterprise computing, cloud computing is massively scalable and flexible. It offers on-demand services through server clusters that are typically geographically distributed.

A cloud architecture incorporates the following key components:

  • At the back-end, resources such as processors, storage, software and data, which are shared as web services. These services include Infrastructure as a Service (IaaS), Platform as a Service (PaaS), Software as a Service (Saas) and Data as a Service (DaaS).
  • At the front-end, client applications, which consume cloud resources and services. This includes downloaded mobile and desktop applications, and web-based applications that are commonly accessed through an online portal.
  • In-between the front- and back-end sits a cloud broker, which connects the client applications to the required services. Think of it as a centralized call center, which mobilizes emergency services when an accident or disaster is reported.

All components of the cloud architecture need to be connected through a network. The biggest vulnerability therefore of cloud computing is poor network connectivity.

Private, Public and Hybrid Cloud

A cloud architecture can be deployed entirely off-premise using third-party cloud services (Public Cloud), entirely on-premise (Private Cloud), or a mix of both (Hybrid Cloud).

  • Public cloud – Infrastructure is owned by one or more service providers that deliver cloud services through the Internet. Individuals and businesses of any size can sign-up for or subscribe to public cloud. There is little or no set-up, and one only requires Internet connectivity and an Internet-enabled device.
  • Private cloud – A business entity owns the cloud infrastructure, which typically resides within their data center. This option is too expensive for small and medium businesses, but offers improved security and benefits of scale to larger organizations. Government may use private cloud to keep their data on-premise in compliance with national legislation.
  • Hybrid cloud – Organizations can combine the benefits of public and private cloud, by off-loading demand for cloud services to the public cloud during peak hours or outages. It also allows them to run their internal business processes in the private cloud, while pushing public data and information services to the public cloud.

IaaS, PaaS and SaaS

Cloud computing offers a complete technology stack through services that are built on top of one another. At the bottom of the stack you will find basic hardware used for storage and computing. At the top of the stack you will find end-user applications that meet business requirements. Cloud services come in three main flavors: IaaS, PaaS and SaaS. Let’s look at them in more detail:

  • IaaS sits at the bottom of the stack and provides basic IT infrastructure such as storage, computing, and virtualization. It’s like a server in the sky, which could have its own data offered as DaaS (Data as a Service). An example of IaaS is Amazon Web Services.
  • PaaS extends the infrastructure to an application framework with the addition of an OS (e.g. Windows Server), a DBMS (e.g. SQL Server) and a development environment (e.g. Visual Studio). An example of PaaS is Microsoft Azure.
  • SaaS provides you with an IT solution that meets your business requirements. It extends PaaS with ready-to-use apps and an information model that maintains the relationships between data and applications. Examples of SaaS are Office 365 and ArcGIS Online.


Cloud is primarily an IT computing architecture, that offers massive scalability and flexibility through on-demand services and resources. Cloud architecture can be accessed through the Internet (public cloud), implemented on-premise (private cloud), or delivered through a hybrid approach (hybrid cloud). Cloud computing offers 3 distinct flavors of cloud services, namely IaaS, PaaS, and SaaS. What are your thoughts on cloud computing and how it can be leveraged in your organization?


About Author: