7The main focus of this book is to introduce the internals of ExFAT File system to the reader and also to compare with the internals of the TexFAT File system in depth. But, as a prerequisite to cover the essential file system fundamental details, this Book starts with introduction of the internals of FAT series file systems such as FAT 12, FAT16 and FAT32. These FAT series file systems are compared with each other in terms of features and limitations and then this book covers the internal details of ExFAT File system and its differentiating features with respect to FAT32 File system. The Transactional features of TFAT and TexFAT File systems are also discussed in detail. This books also discusses how to optimize the FAT and ExFAT File systems for SSDs (Solid State Drives). The data structures used to represent files/directories and algorithms used to manage file system operations of FAT series file systems, ExFAT, TFAT and TexFAT File systems are explained in detail. The snapshots of on-disk structures of files, directories and data of the files/directories are also given along with explanations and indication of the file system parameters so that reader will get the feel of exact internals of how the files/directories are represented and how the on-disk updates are performed by the file system operations. Even though FAT file system is available since HDDs (Hard Disk Drives) era and the specification of FAT File system is available, but in this book, the reader may find the FAT file system explanation with respect to SSDs. The example scenarios of the FAT File system data corruptions are also demonstrated. The on-disk layout snapshots of FAT and other file systems helps the reader to understand the file systems internals easily.This books written with the assumption that the reader need not have any file system knowledge as a prerequisite. Intended audience for this book are computer and information science beginners / students, computer and Information technology (IT) professionals working on SSDs/Flash memories and File systems and the professionals who are interested in doing the forensic analysis on disk file system patterns on storage devices.