This chapter provided a summary of the present state of User Mode Linux (UML) and its user community. It contrasts UML with other visualization technologies, and discusses a bit of UML’s history and purpose. Also, this chapter covers basic concepts of SCSI over Fibre Channel Protocol (FCP) using raw/block device files and volume managers. In addition, it covers block size, multipath I/O drivers, and striping with a volume manager, and concludes with a discussion of filesystem performance and CPU loading. Examples are included for each topic throughout the chapter.