Which describes a Type 1 hypervisor?

• A. Runs directly on bare metal; Examples include ESXi and Hyper-V.
• B. Runs on a host OS; Example VirtualBox.
• C. Is a cloud service model; Example IaaS.
• D. Is a container-based virtualization like Docker.

Answer: (A)

A Type 1 hypervisor is a bare-metal virtualization layer that runs directly on the server hardware. It doesn't depend on a general-purpose operating system, which lets it directly manage CPU, memory, storage, and networking for multiple virtual machines. This direct hardware access gives better performance, stronger isolation, and lower overhead, which is why classic examples are ESXi and Hyper-V in its bare-metal deployment.

The other idea in the choices describes different concepts. A hypervisor that runs on top of a host operating system is a hosted or Type 2 hypervisor, like VirtualBox, which sits above the OS and adds another software layer. The cloud service model (IaaS) is about delivering infrastructure as a service, not how virtualization is implemented. Container-based virtualization like Docker uses OS-level isolation for applications rather than running separate full VMs with their own kernels, so it isn’t a hypervisor running VMs.