Storage management defines the way that an operating system interfaces with nonvolatile storage devices and media. The term storage encompasses many different devices, including optical media, USB flash drives, floppy disks, hard disks, solid state disks (SSDs), network storage such as iSCSI, storage area networks (SANs), and virtual storage such as VHDs (virtual hard disks). Windows provides specialized support for each of these classes of storage media. Because our focus in this book is on the kernel components of Windows, in this chapter we’ll concentrate on just the fundamentals of the hard disk storage subsystem in Windows, which includes support for external disks and flash drives. Significant portions of the support Windows provides for removable media and remote storage (offline archiving) are implemented in user mode.
In this chapter, we’ll examine how kernel-mode device drivers interface file system drivers to disk media, discuss how disks are partitioned, describe the way volume managers abstract and manage volumes, and present the implementation of multipartition disk-management features in Windows, including replicating and dividing file system data across physical disks for reliability and for performance enhancement. We’ll also describe how file system drivers mount volumes they are responsible for managing, and we’ll conclude by discussing drive encryption technology in Windows and support for automatic backups and recovery.