Introduction

In this tutorial, we'll be comparing the three primary cloud service models: Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS). The goal is to help you understand the key differences and similarities between these models and guide you in choosing the right one based on your specific needs.

By the end of this tutorial, you will learn:

• What IaaS, PaaS, and SaaS are
• The advantages and disadvantages of each model
• When to use each model

Prerequisites:

Basic understanding of cloud computing is beneficial but not a must-have.

Step-by-Step Guide

Infrastructure as a Service (IaaS)

IaaS provides the infrastructure such as virtual machines and other resources like virtual-machine disk image library, block and file-based storage, firewalls, load balancers, IP addresses, virtual local area networks, etc.

Examples: AWS, Microsoft Azure, Google Cloud

Advantages:

• Highly flexible and scalable
• No need to invest in and manage own hardware
• Pay-as-you-go model

Disadvantages:

• Can be more expensive in the long run
• Requires technical skills to manage and operate
• Dependent on service provider’s reliability

Platform as a Service (PaaS)

PaaS provides the platform for developers to build applications and services over the internet. This includes development tools, database management systems, business intelligence (BI) services, etc.

Examples: AWS Elastic Beanstalk, Google App Engine, Heroku

Advantages:

• Simple and cost-effective development and deployment of apps
• Scalability, high-availability, and security features are in-built
• DevOps processes can be streamlined

Disadvantages:

• May not support all languages and tools used by developers
• Limited flexibility as applications must comply with platform standards
• Dependent on service provider’s reliability

Software as a Service (SaaS)

SaaS model allows users to connect to and use cloud-based apps over the internet. Examples are email, calendaring and office tools (Microsoft Office 365), etc.

Examples: Google Apps, Salesforce, Dropbox, Slack

Advantages:

• No need to install and maintain software
• Accessible from any location
• Pay-as-you-go model

Disadvantages:

• Limited control and flexibility
• Dependent on internet connectivity
• Data security could be a concern

Summary

In this tutorial, we went through the key differences between IaaS, PaaS, and SaaS, their advantages and disadvantages, and examples.

To further your understanding, you should look into each of these models in more detail and understand their use cases in real-world applications.

Practice Exercises

1. Imagine you are developing a small web application. Which service model would you choose and why?
2. A company is looking to move its existing infrastructure to the cloud. They have a team of experienced IT staff who can manage the systems. Which service model would you suggest to them and why?

Remember, the answers could be subjective and depend on multiple factors.

This tutorial is a starting point and I encourage you to further delve into the subjects and experiment on your own. Cloud computing is vast and continually evolving so keeping up-to-date with the latest trends and technologies is crucial.