Operating Systems · Unit 7
Memory Management
Exam-focused notes for Memory Management (Operating Systems, BIT204): what the TU syllabus asks and how it has actually been tested, with 5 solved past questions from this unit.
What this unit covers
- Virtual memory technique and purpose
- Logical address definition
- Physical address conversion
- Single level paging scheme
- Segmentation with paging
- Swapping definition
- Memory compaction
- Best fit memory allocation
- Coalescing and compaction techniques
Segmentation with paging
Why do we prefer segmentation with paging? Explain. [5]
Both pure segmentation and pure paging have their own limitations. To overcome these limitations, modern operating systems combine both techniques into a hybrid scheme called Segmentation with Paging. --- Pure Paging Pure Segmentation ------ No logical grou...
Full solved answer →Coalescing and compaction techniques
Write down the basic difference between coalescing and compaction with diagram. [5]
--- Definition: Coalescing is the process of merging two or more adjacent free memory blocks into a single larger free block when a block is deallocated. - It happens immediately when a block is freed and its neighbor(s) are also free. - It only combines ph...
Full solved answer →Memory compaction
What is memory compaction? Explain best fit memory allocation with suitable example. [5]
Memory compaction is a memory management technique used to overcome the problem of external fragmentation. When processes are loaded and removed from memory over time, free memory becomes scattered in small, non-contiguous blocks. Even if the total free mem...
Full solved answer →Virtual memory technique and purpose
Why virtual memory technique is used in the computer system? What is logical address? Explain the process of conversion of logical address to physical address in single level paging scheme.[10]
Note: Reference notes were not available for this topic. The answer below is based on standard Operating Systems curriculum as taught in TU BSc CSIT (consistent with Silberschatz/Galvin and similar texts used in the program). --- Virtual memory is a memory ...
Full solved answer →Swapping definition
Define swapping. How does the OS manage the virtual memory? [5]
--- Swapping is a memory management technique in which a process (or a portion of a process) is temporarily moved out of main memory (RAM) to a backing store (usually a hard disk or swap space), and later brought back into memory for continued execution. - ...
Full solved answer →Make Unit 7 stick
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