With the advancement of computer, mobile and popularity of internet and social media, digital data is growing exponentially. Current total global data is almost double than what was there two years back. Computer storage technologies have become most important and critical that supports this enormous growth of digital data and stores them more efficiently. Therefore demand for computer storage knowledge increased drastically in recent years.This book explains the basic concept of computer storage and its fundamental features and functionalities. It also includes topics on how the application servers access storage systems through the network. Different storage vendors use different name for physical and logical components of a storage system, but this book primarily focuses on the concept of storage systems using simple and commonly understood terminologies. Almost all modern storage systems have virtualization implemented to enhance performance and fault tolerance. This book explains these implementation aspects in simple terms.