2.1.What is Cloud Computing?

Cloud computing is a transformative technology that has redefined the landscape of information technology and business operations over the last two decades. It is a broad term that encompasses a range of services delivered on demand to companies and customers over the internet. These services are designed to provide easy, affordable access to applications and resources, without the need for internal infrastructure or hardware.

The Essence of Cloud Computing

At its core, cloud computing is the delivery of computing services—including servers, storage, databases, networking, software, analytics, and intelligence—over the Internet (“the cloud”) to offer faster innovation, flexible resources, and economies of scale. You typically pay only for cloud services you use, helping lower operating costs, run infrastructure more efficiently, and scale as your business needs change.

The defining features of cloud computing include on-demand self-service, broad network access, resource pooling, rapid elasticity, and measured service. These characteristics outline the fundamental attributes that make cloud computing so powerful and advantageous for businesses and individuals alike.

The Evolution of Cloud Computing

To understand what cloud computing is today, it’s helpful to look at the evolution of computing paradigms over the years. Traditionally, businesses and individuals managed physical hardware and software on their premises. This approach was capital intensive and lacked flexibility, as it required significant upfront investments in infrastructure and a workforce to manage it.

The arrival of virtualization technology marked the beginning of the shift towards cloud computing. Virtualization allows for the creation of a simulated, digital-only “virtual” computer that behaves as if it were a physical computer, which led to more efficient utilization of resources. It set the stage for the development of cloud services, where multiple virtual systems could be run on a single physical system, maximizing efficiency and reducing costs.

Service Models of Cloud Computing

Cloud computing is often categorized into three service models, which form the pillars upon which the cloud stands:

  1. Infrastructure as a Service (IaaS): This is the most basic category of cloud computing services that allows you to rent IT infrastructure—servers and virtual machines (VMs), storage, networks, operating systems—from a cloud provider on a pay-as-you-go basis.
  2. Platform as a Service (PaaS): Designed to support the complete web application lifecycle of building, testing, deploying, managing, and updating, PaaS provides a platform allowing customers to develop, run, and manage applications without the complexity of building and maintaining the infrastructure typically associated with developing and launching an app.
  3. Software as a Service (SaaS): SaaS delivers software applications over the internet, on-demand and typically on a subscription basis. With SaaS, cloud providers host and manage the software application and underlying infrastructure and handle any maintenance, such as software upgrades and security patching.