Advanced Topics

Virtualization permeates all aspects of computing. Virtual machines are one instance of this trend. Generally, with a virtual machine, guest operat- ing systems and applications run in an environment that appears to them to be native hardware. This environment behaves toward them as native hardware would but also protects, manages, and limits them.

A distributed system is a collection of processors that do not share memory or a clock. Instead, each processor has its own local memory, and the processors communicate with one another through a local-area or wide-area computer network. Computer networks allow disparate computing devices to communicate by adopting standard communica- tion protocols. Distributed systems offer several benefits: they give users access to more of the resources maintained by the system, boost com- putation speed, and improve data availability and reliability.