onsumers as well as business customers created the tsunami of rapid change. This escalation was made possible in large part by the introduction of fiber optics, the development of multiprocessing computer chips integrated into various types of network equipment, and the decrease in prices of mass computer storage. These factors along with the shrinking size of components are continuing to lead to vast improve- ments in mobile networks and mobile devices as well as land-based networks and consumer electronics. Children born in the twenty-first century have trouble imagin- ing a world without e-mail and cell phones. These innovations will lead to even faster changes in the future. A significant shift in computing is occurring with the introduction of virtualiza- tion, which came about because of more powerful networks and computers. Server tualization is the capability of servers to store and run multiple operating systems, each running multiple applications. Servers are specialized computers that host applications such as e-mail or web pages. They can also host applications such as accounting and sales automation packages. The capability of virtualization to consolidate a large num- ber of servers has resulted in the capability of data centers to consume less space and electricity and require fewer administrative tasks. It has also brought down the costs for large third-party providers to manage expansive data centers. Virtualization and powerful networks are the key factors that have enabled cloud computing offerings to be viable. Cloud computing is when consumers, small busi- nesses, and large organizations move some or all of their computing needs to external providers, who typically maintain large data centers. Clients usually access the appli- cations and data that reside in these data centers via the Internet. Because it is relatively new, most large commercial customers start out by using the cloud for applications that are important but not critical to their core offerings. These include human resources sy