In today's lecture we are exploring the concepts of segmentation and free space management, focusing on memory management within operating systems. We start with a review of address spaces, emphasizing their role as the abstraction that programs use to access memory, providing them the illusion of a contiguous space. The lecture then addresses the limitations and challenges associated with the base and bounds method, such as the restriction on the total memory available for all processes and the issues of fragmentation. We introduce segmentation as an alternative approach, dividing memory into segments (like code, heap, and stack), each with its own base and bounds, to efficiently utilize available memory space and reduce fragmentation.
As the lecture progresses, we look into the handling of segmentation faults, the impact of the segmentation model on modern operating systems, and the practical aspects of segment allocation and free space management. We compare different segmentation strategies (fine-grained vs. coarse-grained) and examine the OS's role in dynamically allocating and managing these segments. The concept of external fragmentation is discussed, along with strategies like compaction and the use of free-list management algorithms to mitigate its effects. We conclude with an in-depth look at memory allocation techniques (best fit, worst fit, first fit, next fit, and size class allocator) and their implications for system performance and memory utilization efficiency. This lecture is not just about providing foundational knowledge on memory management strategies but also about emphasizing the importance of efficient space allocation and management in operating systems, in real-time.
https://docs.google.com/presentation/d/1F56zKcGfoQBoeUqRqJWt0xjyWNAlBWUAxf9Y7JiPk54/edit?usp=sharing
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