Os Memory Management Questions
Segmentation is a memory management technique that divides the main memory into variable-sized segments, where each segment represents a logical unit of a program. The process of segmentation involves the following steps:
1. Segmentation Table Creation: A segmentation table is created to keep track of the segments in memory. Each entry in the table contains the base address and the length of the segment.
2. Program Segmentation: The program is divided into logical segments based on its structure and requirements. These segments can include code, data, stack, heap, and other segments.
3. Segment Allocation: When a program is loaded into memory, the operating system allocates memory segments to the program based on its segment requirements. The allocated segments are then mapped to the corresponding entries in the segmentation table.
4. Address Translation: Whenever a program references a memory location, the logical address is divided into two parts: the segment number and the offset within the segment. The segment number is used to index the segmentation table and retrieve the base address of the segment.
5. Base Address Addition: The base address of the segment is added to the offset to obtain the physical address in memory. This physical address is then used to access the actual data or instruction.
6. Protection and Sharing: Segmentation allows for protection and sharing of segments. Each segment can be assigned different access rights, such as read-only or read-write, to protect the integrity of the program. Segments can also be shared among multiple processes, reducing memory duplication.
Overall, segmentation provides a flexible and efficient way to manage memory by dividing it into logical units, allowing for better memory utilization and protection.