Virtualization and emulation are inherently fascinating topics. Why should you need to have multiple computers running multiple operating systems when one computer can run them all? Even better, if you have a sufficiently powerful machine, why limit yourself to running only one operating system at a time?
Savvy IBM mainframe users greet virtualization with a yawn and a statement like "That old thing?" Thousands of IBM systems have been running critical business tasks in virtual machines on mainframes for a few decades now. Originally introduced as a mechanism to simultaneously support legacy and more modern operating systems on newer hardware without requiring software changes, virtualization has been a part of enterprise computing since the 1960s.
The emergence of powerful, affordable, open source virtualization has taken a long time. As this book illustrates, today's virtualization technologies have an important place in today's powerful, 24/7 enterprise computing environments. Virtualization can help you get the most out of your existing hardware; reduce data center costs; help guarantee the seamless availability of critical systems; help support "occasional-use" legacy applications without requiring aging, hard-to-replace hardware; and much, much more.
I refer to today's virtualization technologies as "commodity" virtualization technologies because they run on standard, off-the-shelf hardware using a variety of readily available operating systems such as Linux — no ...