Windows Internals covering windows server 2008 and windows vista- P13

Windows Internals covering windows server 2008 and windows vista- P13: In this chapter, we’ll introduce the key Microsoft Windows operating system concepts andterms we’ll be using throughout this book, such as the Windows API, processes, threads, virtualmemory, kernel mode and user mode, objects, handles, security, and the registry.
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Windows Internals covering windows server 2008 and windows vista- P13 I/O system objects, including driver and device objects. Internally, the Windows I/O system operates asynchronously to achieve high performance and provides both synchronous and asynchronous I/O capabilities to user-mode applications. Device drivers include not only traditional hardware device drivers but also file system, network, and layered filter drivers. All drivers have a common structure and communicate with one another and the I/O manager by using common mechanisms. The I/O system interfaces allow drivers to be written in a high-level language to lessen development time and to enhance their portability. Because drivers present a common structure to the operating system, they can be layered one on top of another to achieve modularity and reduce duplication between drivers. Also, all Windows device drivers should be designed to work correctly on multiprocessor systems. Finally, the role of the PnP manager is to work with device drivers to dynamically detect hardware devices and to build an internal device tree that guides hardware device enumeration and driver installation. The power manager works with device drivers to move devices into low-power states when applicable to conserve energy and prolong battery life. Four more upcoming chapters in the book will cover additional topics related to the I/O system: storage management, file systems (including details on the NTFS file system), the cache manager, and networking. 590Please purchase PDF Split-Merge on www.verypdf.com to remove this watermark. 8. Storage Management Storage management defines the way that an operating system interfaces with nonvolatile storage devices and media. The term storage encompasses many different devices, including tape drives, optical media, USB flash drives, floppy disks, hard disks, network storage such as iSCSI, and storage area networks (SANs). 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. 8.1 Storage Terminology To fully understand the rest of this chapter, you need to be familiar with some basic terminology: ■ Disks are physical storage devices such as a hard disk, a 3.5-inch floppy disk, or a CD-ROM. ■ A disk is divided into sectors, which are addressable blocks of fixed size. Sector sizes are determined by hardware. Most hard disk sectors are 512 bytes, and CD-ROM sectors are typically 2048 bytes. ■ Partitions are collections of contiguous sectors on a disk. A partition table or other diskmanagement database stores a partition’s starting sector, size, and other characteristics and is located on the same disk as the partition. ■ Simple volumes are objects that represent sectors from a single partition that file system drivers manage as a single unit. ■ Multipartition volumes are objects that represent sectors from multiple partitions and that file system drivers manage as a single unit. Multipartition volumes offer performance, reliability, and sizing features that simple volumes do not. 591Please purcha ...