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. 

CST 334 Week 7 Report

 This week, we learned a ton about the fundamentals of persistence in operating systems. We started by looking at basic device interactions with the operating system. The device itself requires two parts to make interaction efficient: the hardware interface and its internal structure. There are three main mechanisms employed to reduce CPU overhead: interruption system, programmed I/O, and direct memory access (DMA). For systems with larger memory volume transactions, DMA is superior, especially if data transactions are frequent, because the CPU does not have to be constantly used during transfers. When it comes to how the OS interacts with the device, there are two primary methods: one is to have explicit I/O instructions, and the second is known as memory-mapped I/O. Finally, the device driver is what specifically abstracts the device function away from the OS by way of a piece of software that details how a device works. Afterwards, we learned about the basics of hard disk drives. Modern disks have a platter and a spindle. Data is encoded on each surface in concentric circles of sectors that are called tracks. We read data from the surface with a disk head and arm. There are numerous disk I/O scheduling algorithms that can be employed, from more basic ones like first come, first serve to modernized algorithms like budget fair queuing. When it comes to file systems, we learned about persistent storage and devices like HDDs and SSDs. The two basic abstractions developed regarding storage are files and directories, which comprise the bread and butter of persistence in the OS. We explored the file system interface including creating, accessing, and deleting files. We wrapped up our week by learning a simple file system implementation through the vsfs (very simple file system), which is a simplified version of a typical UNIX file system. When thinking of file systems, we should be thinking about two primary aspects: the data structures of the file system and the access methods required to actually do things with data. We learned about the Inode, or index node which is the structure that holds metadata for a given file. We were able to learn more about multi-level indexing, directory organization, and free space management within a file system. All in all, it was a good week of learning and I hope we can continue to build on these basic concepts.