Fragmentation and Segmentation: Memory Management Techniques

This lecture discusses the concepts of fragmentation and segmentation in computer systems. It begins with an overview of fragmentation, explaining how it leads to inefficient use of storage space, which can reduce both capacity and performance. The instructor describes two types of fragmentation: internal and external. Internal fragmentation occurs within a process, while external fragmentation arises when free memory is not contiguous, preventing the allocation of new processes. The lecture illustrates external fragmentation with examples of processes and memory allocation scenarios. The solution to fragmentation is presented as segmentation, which allows multiple base and bound registers for different memory areas, enhancing flexibility in memory allocation. The benefits of segmentation over traditional methods are highlighted, including reduced memory waste and improved sharing through protection bits. However, the lecture also addresses the limitations of segmentation, such as the requirement for physical memory backing for each segment. The session concludes with a summary of memory virtualization techniques and the historical context of segmentation in early computer architectures.