CST 334 Week 8 Report

This week, we delved more deeply into the essentials of persistence in operating systems. We began by examining the fundamental interactions between the OS and hardware devices. Efficient communication with a device relies on two key components: the hardware interface and its internal organization. To minimize CPU load, three main techniques are used: interrupt-driven I/O, programmed I/O, and direct memory access (DMA). DMA is particularly advantageous for systems handling large volumes of data, especially with frequent transactions, as it reduces the need for constant CPU involvement during data transfers. We also studied the ways the OS interacts with devices, focusing on explicit I/O instructions and memory-mapped I/O. Additionally, we learned that device drivers play a crucial role in abstracting device operations from the OS, through software that defines the device's functionality. Our exploration continued with the basics of hard disk drives. Modern hard disks feature a platter and spindle, with data stored in concentric circles called tracks on each surface. A disk head and arm are used to read this data. Various disk I/O scheduling algorithms were discussed, ranging from simple methods like first-come, first-served to more advanced ones such as budget fair queuing. In the realm of file systems, we covered persistent storage devices like HDDs and SSDs. We focused on the core abstractions of storage: files and directories, which are fundamental to data persistence in the OS. We explored the file system interface, including file creation, access, and deletion. We concluded the week by implementing a basic file system using vsfs (Very Simple File System), a simplified model of a typical UNIX file system. Key takeaways included understanding the structure and access methods of file systems, learning about the Inode (index node) for file metadata, and exploring multi-level indexing, directory organization, and free space management. Overall, it was a productive week of learning, and I look forward to building on these foundational concepts.

When it comes to persistence of personal character, I learned quite a bit over the course. I learned that even when I am confused during an assignment, to simply sit with the challenge and continuously examine it until it truly sinks into my understanding. I also learned that I can sometimes rely on others to clarify for me instead of trying to brute force solve it on my own. Thankfully, Dr. Ogden was helpful in slack and helped to clear up any confusions. I learned that by developing more resilience and discipline, I can accomplish any task as long as I stay focused. Thanks.