CST334 Module 4

What did I learn in the fourth week of CST334?

This week I learned about another four different topics about operating systems. The first topic was about paging, which is a strategy for dividing virtual and physical memory. Basically, paging divides both types of memory into a fixed size called pages for virtual and frames for physical. Paging can avoid fragmentation through non-contiguous allocation, thus through a page table mapping the virtual and physical memory, enables proper memory management. The second topic was about translation lookaside buffers (TLB), which is a hardware-level cache that can store the recent virtual-to-physical address translations. Basically, TLBs are quick accesses in managing a CPU, as they reduce overhead, while maintaining performance by speeding up memory access in paging systems and frequent memory operations.

The third topic was about multi-level paging, which is a strategy or concept that breaks a part flat page tables into multiple levels, similarly to a tree structure. Basically, multi-level paging is all about improving scalability and preventing the use of a large amount of memory. Therefore, memory usage is sparce when using multi-level paging, which provides parts of the page table that are either created or loaded as needed. The final topic was about swapping, which extends memory through a temporary move of inactive pages. Basically, whenever RAM is overloaded, the operating system swaps pages to the disk storage, maintaining active working sets. However, it introduces latency, as swapping in and out of RAM to disk storage can tank performance, even though swapping can enable multitasking beyond physical memory limits.