In cloud computing, which service model provides the most control over the operating system and applications?

• A. PaaS
• B. IaaS
• C. SaaS
• D. FaaS

Answer: (B)

Cloud service models define who handles each part of the stack, and the more you can customize and manage the operating system and software, the more control you have. Infrastructur e as a Service gives you virtual machines where you choose and configure the operating system, install and manage software, patch and harden the OS, and control the software stack. The provider only takes care of the underlying hardware, virtualization, and basic networking. This is why it offers the most control over the OS and applications. In contrast, Platform as a Service abstracts away the OS and runtime so you focus on your code and data, Software as a Service runs applications for you with minimal customization, and Functions as a Service handles code execution in managed environments with even less control over the underlying system.