CST 334 Week 7

This week in week 7 in CST 334, we learned about file systems IO devices, and persistent storage management. We learned that files serve as a key abstraction provided by the operating system. They are linear arrays of bytes stored on a disk permanently. The files are organized into directories which form a hierarchical structure that maps human readable file names to lower level identifiers like inode numbers. To implement a file system you need to manage various on disk structures like data blocks, nodes, allocation bitmaps, and a superblock that has high level info about the file system. inodes also store metadata like file size, ownership and block pointers. we then saw file systems layouts like system V file system, which has a centralized node table, and then the Berkeley Fast File System, FFS, which improves performance by grouping related data and meta data into cylinder groups. And to support large files nodes use techniques like multi level indexing through indirect pointers. Lastly we looked at methods that can ensure file system readability including regular backups which can be full or incremental. There are also file system consistency checks to recover from crashes. To have better performance, operating systems use caching ti keep frequently accessed data in the memory and apply the proper block allocation strategies. We also studied the mechanics of hard drives like how platters, tracks, and sectors work and how their performance is affected by seek time or rotational leniency. There was also RAID techniques or redundant array of independent disks that are used to combine disks to boost performance, capacity, and reliability.