Virtualization Principles: Mechanisms and Applications

This lecture revisits the concept of virtualization, focusing on its fundamental principles and mechanisms. It begins by defining virtualization as an application of the principle of indirection, which states that any problem in computer science can be solved by adding a level of indirection. The instructor explains that virtualization requires a layer that exports a compatible abstraction while ensuring isolation from the underlying physical resources. Three main mechanisms of virtualization are discussed: multiplexing, which exposes a single resource among multiple virtual entities; aggregation, which makes multiple resources appear as a single virtual resource; and emulation, which allows a physical resource to appear as another. The lecture also reviews the implementation of virtual memory, highlighting how it utilizes multiplexing through hardware components like the translation lookaside buffer (TLB). The importance of the operating system in maintaining isolation and managing virtual memory is emphasized, along with applications such as context switching and demand paging. The session concludes with a summary of the principles and techniques covered, setting the stage for further exploration of aggregation and emulation in the next module.