Chapter 11: Mass-Storage Structure: HDD, NVM, RAID, and Swap-Space Management

Mass-Storage Structure: HDD, NVM, RAID, and Swap-Space Management begins by describing disk structure, including platters, tracks, sectors, and cylinders, and explains how disk heads access data through seek, rotational, and transfer times. Disk scheduling algorithms—such as FCFS, SSTF, SCAN, C-SCAN, LOOK, and C-LOOK—are presented with discussions on performance trade-offs. The chapter explores SSD architecture, contrasting it with traditional disks in terms of latency, throughput, endurance, and wear leveling. RAID (Redundant Array of Independent Disks) is introduced as a technique for improving reliability and performance, with detailed coverage of RAID levels, parity, and striping. It also addresses disk management tasks such as low-level formatting, partitioning, and file system mounting, as well as swap-space management for virtual memory. The discussion expands to include tertiary storage devices like optical disks and magnetic tapes, focusing on their use cases and limitations. Finally, the chapter examines storage performance metrics, I/O buffering, caching strategies, and storage hierarchies, tying these concepts to real-world operating system implementations. By the end, readers gain a clear understanding of how OSes manage mass storage for speed, reliability, and cost efficiency.