An introduction to cloud computing right from the basics up to IaaS, PaaS and SaaS

By An introduction to cloud computing right from the basics up to IaaS, PaaS and SaaS

Cloud computing is the model of delivering applications, storage, and processing power (on-demand computing services and resources) over the internet through web-based applications. In cloud computing, you don’t access services from your computer’s hard-drive or data centers, instead, you rent access to services and resources from a cloud service provider like AWS and Azure.

The advantage of cloud computing is that companies will not incur the costs of installation as well as maintenance of their own IT infrastructure or data centers. They will simply pay for what they use and only when they use it. Cloud service providers benefit from large economies of scale, in that they provide the same services to many customers.

Cloud computing services

Cloud computing services range from storage, networking, processing power, office applications, natural language processing, and AI. Any service that you use without the need of being physically near the computer can be delivered through the cloud.

Services like Gmail, drive, and cloud back-ups on your phone are examples of cloud computing targeting individuals. Companies can rely on cloud computing for hosting media files like videos and images and running their applications in the cloud. For example, Netflix relies on cloud computing services to run its video streaming service and its other business systems too.

Many software vendors are progressively offering their apps as a service over the internet instead of offering standalone software apps as cloud computing becomes the default option for them. The downside is that this can bring in new costs and potential risks to companies using cloud computing.

History of cloud computing

The term cloud computing has been in existence since the early 2000s, although the concept of computing-as-a-service has been there as early as the 1960s. This is when computer bureaus could permit firms to rent time on a mainframe computer, rather than buying it. The introduction of PCs, personal computers, made owning a computer much more affordable hence, the rate of renting mainframes largely declined. Also, there was more rise in corporate data centers as companies would store large amounts of data. The concept of renting access to computing power has emerged many times.

The name cloud computing was coined from the basis that the location of the service, the hardware and the operating system used are very irrelevant to the end-user. It's with this in mind that the metaphor of the cloud was borrowed from old telecoms network schematics, in which the public telephone network (and later the internet) was often represented as a cloud to denote that the just didn't matter -- it was just a cloud of stuff.

Cloud computing brought the emergence of software as a service and as a result, we have seen many cloud computing service providers like AWS and Azure.

Three cloud computing service models

Cloud computing is broken down into three models:

  1. Infrastructure-as-a-Service (IaaS)
  2. Platform-as-a-Service
  3. Software-as-a-Service

IaaS (Infrastructure as a Service)

This involves hardware and software combinations to build everything on your own. Users can configure essential computing devices, operating system, and other applications on their own. They can manage some network devices, storage, and the platform. But, they are not allowed to fully control the physical infrastructure on their own. Three central parts of computing, i.e. CPU, Memory, and Disk can be rented or provisioned on the cloud. Example of IaaS is Amazon's S3, Google Compute Engine, Oracle Storage Cloud, or Oracle Bare Metal Cloud. The infrastructure and business model is categorized into being shared or dedicated to a particular company, being stored externally or externally and the client's authority to interact and customize the system. Users assess the cost of the system, level of control, and scalability of the system when considering it.

PaaS (Platform as a Service)

This involves tools and services to develop and deploy applications. Examples of PaaS are Google App Engine, Java Cloud Service, Database as a Service, etc. The provider offers a computing environment for users to develop, manage, and run their applications using programming languages and databases. Additionally, users can utilize a suite of prebuilt tools to create, customize, and test their applications. In this model, clients are not allowed to control or manage the servers, platform (OS), storage capacities, and different components that constitute the platform infrastructure. Clients' position is restricted to changes related to the applications sent to the cloud and setup settings of the platform the software runs on. The model facilitates collaborative work regardless of whether groups work remotely.

SaaS (Software as a Service)

This involves ready-made applications to be used by its end-users. Examples of SaaS are Gmail, DropBox, Oracle Fusion Applications, Salesforce, Workday, etc. The service providers give multiple users access to the application software which is hosted on the server. Clients don't install applications on their local computers. Rather, the applications dwell on remote cloud storage accessed through the web or an API. Through the application, clients can store and analyze information and work together on their projects. Clients are allowed to make alterations in the settings of the specific software. In this model, the software is provided as a service through the Internet, and the service is priced on a pay-per-use basis.

Advantages of Cloud computing

  1. It helps you to save substantial capital costs as it does not need any physical hardware investments or trained personnel to maintain the hardware.
  2. Since cloud computing offers a competitive edge, you get the latest applications anytime without spending time and installation costs.
  3. Cloud computing enables you to deploy your services faster.
  4. Back-up and restoring data is easy and quicker when the data is stored in a Cloud.
  5. You can always get instant updates and changes.
  6. Employees who are working on the premises or at the remote locations can easily access all the could services. All they need is Internet connectivity.
  7. The cloud computing platform helps employees who are located in different geographies to collaborate in a highly convenient and secure manner.

Disadvantages of Cloud Computing

  1. Your business must always have an internet connection to reap the full benefits of cloud computing.
  2. You may experience limited storage space or accessibility. SaaS offerings may usually begin with a free package, but you will be charged for premium offerings and extra space.
  3. Lack of control of your data. You have to trust that your provider’s data centers are compliant and secured both physically and online.
  4. Cloud hacking cases as recent as the past few months have shown that not all cloud providers are as secure as they claim to be.
  5. If you experience any technical issues, you have no choice but to call your hosted provider’s technical support for help.


Cloud computing, public or private, has become the platform of choice for large applications, particularly customer-facing ones that need to change frequently or scale dynamically. More significantly, the major public clouds now lead the way in enterprise technology development, debuting new advances before they appear anywhere else. Workload by workload, enterprises are opting for the cloud, where an endless parade of exciting new technologies invites innovative use.

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Eric Murithi Muchenah

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