programs or inadvertently open e-mail attachments that contain viruses can unwit- tingly bring computer networks to their knees. All of these factors plus improvements in desktop virtualization are pushing an interest in desktop virtualization by large enterprises. With desktop virtualization, users have a screen, keyboard, and small connector box in their offices rather than a com- plete computer. The connector box is tied to a centralized server that runs desktop vir- tualization software. User desktops are hosted in the central server. When a user turns on his screen, he sees an image of his desktop, complete with icons. This is referred to as thin-client technology because very little intelligence is located at the end user's device. The user's equipment is referred to as the client. Organizations such as Citrix Systems, Inc., Microsoft, and VMware supply desktop virtualization software. In the past, when desktop virtualization was tested, most organizations that installed it experienced unacceptable delays in accessing centralized files and appli- cations. Improvements have eliminated these delays. However, initial costs for the centralized server and software and end-user devices are inhibiting factors. This is particularly true if laptops or desktop computers are new and not fully depreciated. Another factor inhibiting implementation is the fear that if a remote user wants to work on centralized files, and she is not somewhere with an available broadband connection, productivity gains in centralizing applications and any modifications to the files will be lost. MANAGING VIRTUALIZATION Organizations can take advantage of many benefits by implementing virtualization capability in servers and storage networks. They also take on challenges managing them in complex environments. Managing Memory, CPUs, and Storage in Virtualized Data Centers Server and storage virtualization have many benefits, including saving money on elec- tricity, heating, and cooling. However, there are challenges in large data centers. One