Storage Hierarchy: Understanding Data Management Systems

This lecture covers the storage hierarchy in data-intensive systems, focusing on the various storage layers including CPU registers, caches, DRAM, SSDs, and HDDs. The instructor explains the importance of understanding latency and access times for different storage types, emphasizing the cost implications of read and write operations in database management systems (DBMS). The lecture also discusses why data cannot be stored solely in main memory due to cost and volatility, and highlights the role of disks as secondary storage media. The instructor elaborates on the mechanics of HDDs and SSDs, including their performance characteristics and the significance of data organization on disk. Additionally, the lecture introduces buffer management, explaining how DBMS manages data in memory and the policies for page replacement. Various algorithms for buffer management, such as FIFO, LRU, and clock, are discussed, along with their advantages and limitations. The session concludes with a summary of key concepts related to efficient data storage and retrieval in modern systems.