There are three layers involved in running modern computer systems:
At the lowest level is the infrastructure.
This refers to the physical and virtual hardware needed to run computing systems. Infrastructure includes components such as servers, storage devices, networking equipment, and data centres. It also includes virtualization technology that allows multiple virtual machines to run on the same physical hardware.
Infrastructure provides the foundation that everything else depends on.
Built on top of the infrastructure is the platform.
A platform provides the environment needed for developers to create, test, and run applications. This includes operating systems, databases, web servers, programming language environments, and development tools.
The platform acts as a bridge between the raw hardware (infrastructure) and the software applications used by end users.
At the top layer is the software itself.
Software refers to the applications that users interact with directly, such as word processors, email systems, video conferencing tools, or online games.
These applications perform specific tasks for users without requiring them to manage the underlying platform or infrastructure.
These three layers form the basis of cloud computing service models:
Infrastructure as a Service (IaaS) provides access to infrastructure resources.
Platform as a Service (PaaS) provides both infrastructure and a development platform.
Software as a Service (SaaS) provides complete software applications ready for end users.
Understanding these layers helps explain how responsibility is divided between cloud providers and customers in different cloud service models.
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