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What is Cloud Computing?

Cloud computing is a service model that helps customers to obtain IT computing resources over the internet.


Cloud computing explained

The name “the cloud” for cloud computing is rooted in “the [cloud] symbol used in [cloud computing] conceptual network diagrams from the 1970s”.1

A Cloud Guru editor succinctly defines cloud computing or the cloud as “a pool of computer services accessed over the internet [that are] accessible on-demand and self-service, giving instant access to services without setup [and making it possible for] computers that businesses once had to have on-premises [to] be stored in massive data centers* around the world”.1

The cloud computing definition can be expanded to include “cloud computing as a service model”2 that incorporates “in network diagrams and flowcharts, an icon that resembles a cloud is traditionally used to represent the internet”.2 Margaret Rouse notes that each cloud computing environment contains the following five characteristics to distinguish itself from a standard computing environment:

  • Self Service – the customer can provision computing resources by themselves, on demand.
  • Network Access – resources are provisioned and accessed over the internet.
  • Resource Pools – resources are pooled together to serve the needs of multiple customers.
  • Elasticity – resources can be rapidly provisioned or scaled down depending on real-time need.
  • Measured Services – resource usage can be monitored and controlled by the customer.2

What are the cloud deployment models? 

The several different options for enterprises looking to deploy their data and infrastructure onto the cloud consist of the following examples:  

  • Public Clouds – allow resources to be accessed by authorized subscribers.
  • Private Clouds – restrict resource access to a specific group or organization.
  • Community Clouds – allow resources to be shared among two or more organizations.
  • Hybrid Clouds – resources are provided by at least two cloud service providers.2

What are the types of cloud computing service delivery models?

If cloud computing is the delivery of computing resources to customers over the internet, then cloud computing services are a way to faciliate that delivery from certain delivery models.

The four types of cloud computing service delivery models consist of the following:

  1. Infrastructure as a service (IaaS) provides users with compute, networking, and storage resources.
  2. Platform as a service (PaaS) provides users with a platform on which applications can run, as well as all the IT infrastructure required for it to run.
  3. Software as a service (SaaS) [essentially] provides users with a cloud application, the platform on which it runs, and the platform’s underlying infrastructure.
  4. Function as a service (FaaS) [is] an event-driven execution model [that] lets developers build, run, and manage app packages as functions without maintaining the infrastructure.

The Red Hat authors note that “all infrastructure, platforms, software, or technologies that users access through the internet without requiring additional software downloads can be considered cloud computing services—including the following as-a-Service solutions”.2

What are the three basic types of cloud "as a service" models?

Rouse argues that the three basic types of cloud service delivery models for establishing the foundation for your cloud migration consist of the following examples: 

Software as a Service (SaaS): 

The ACG Technical Editors Team describes SaaS simply as “software provided over the internet [where] nothing is installed on a local computer, tablet, or phone [and] no one is needed to manage things like patches or updates. It just works”.1

In the AppNeta page, “SaaS, IaaS or PaaS: Which Cloud Migration Option Is Right for You?”, author Joe Michalowski writes that “SaaS is the most popular means of migration [with a] web delivery model [that] makes SaaS a premier way for companies to realize the cost-savings benefits of cloud computing”.3

It’s easy for an enterprise to leverage “SaaS for specific tasks and processes while eliminating many small IT maintenance tasks [instead of] installing applications across the enterprise”.3

Several examples of SaaS include:

  • Google Suite apps
  • Salesforce
  • GoToMeeting
  • Dropbox
  • Microsoft 365

Platform as a Service (PaaS):

The ACG Team defines PaaS as “a software building ground for developers [where you can] just BYO applications and data”.2 They note that it “provides a blank slate in the cloud that lets the developers create, deploy, and scale applications without having to [worry over] things like infrastructure, storage, or operating system (OS)”.1

More complex than SaaS and “accessible for businesses of all sizes”,3 PaaS helps enterprises to “embrace components of cloud computing [that] you can develop on top of [and] customize apps to your specific business needs while enjoying benefits like scalability, high availability [etc.]”.3

Michalowski notes that while enterprise can deploy PaaS partially with their public cloud infrastructure, “many companies enjoy the benefits of keeping it entirely on premises”.3

Several examples of PaaS include:

  • AWS Elastic Beanstalk
  • OpenShift
  • Google App Engine

Infrastructure as a Service (IaaS)

The ACG Team defines IaaS as simply “moving infrastructure to the cloud [similar to] renting a server in the cloud [where] your cloud provider owns the hardware and is responsible for managing and maintaining it, [and] you don’t have to worry about any maintenance”.1

Michalowski describes IaaS as “the category you’re talking about when considering a strict public cloud migration”.3 Contrary to the ACT Technical Editors Team’s description, writes that “unlike SaaS and PaaS, an IaaS migration leaves you completely responsible for managing everything from applications and data to operating systems in the cloud”.3

IaaS allows enterprises to “extend [their] data center infrastructure with near-unlimited scalability while retaining the freedom to use any software or platform you need”.3

Several examples of IaaS include:

  • Amazon Web Services (AWS)
  • Microsoft Azure
  • Google Cloud Platform


  1. ACG Technical Editors Team, What is Cloud Migration?, A Cloud Guru, 14 July 2022.
  2. Margaret Rouse, Cloud Computing, Techopedia, 27 April 2022.
  3. Joe Michalowski, SaaS, IaaS or PaaS: Which Cloud Migration Option Is Right for You?, AppNeta, 21 February 2017.