In virtual machines, which type of virtualization allows only some of its components to be virtualized?

Partial virtualization refers to a type of virtualization where only specific components or aspects of the system's architecture are virtualized, while others remain non-virtualized. This approach allows the system to manage resources more flexibly by leveraging both physical and virtual components.

In partial virtualization, the hypervisor may virtualize key system resources, such as memory or CPU, but leave other components, such as I/O devices, partially emulated or directly mapped to the host's hardware. This contrasts with full virtualization, which creates a complete and independent virtual environment, where the guest operating systems are abstracted from the physical hardware entirely.

Understanding partial virtualization is important in scenarios where performance is critical, and direct access to hardware components may be required for certain applications or workloads. It provides a middle ground between the efficiency of running on physical hardware and the flexibility offered by full virtualization solutions.