OS( MEMORY MANAGEMENT)

These notes provide a clear and structured overview of one of the most critical areas in Operating Systems — **Memory Management**. They are designed to break down technical concepts into easy-to-understand segments, supported by diagrams, examples, and comparisons that aid quick revision and deep understanding. The notes begin with the basics of memory hierarchy and the role of the operating system in managing memory efficiently. Topics include **contiguous memory allocation**, **partitioning**, and **fragmentation** (internal and external), explained with step-by-step visuals. A major focus is placed on **paging** and **segmentation**, along with the differences between the two and how they help overcome fragmentation issues. You’ll also find detailed explanations of **virtual memory**, **demand paging**, **page replacement algorithms** (like FIFO, LRU, Optimal), and **thrashing** — all explained with solved examples, page tables, and reference string analysis. Whether you’re preparing for university exams or building foundational knowledge for systems programming, these notes are tailored to give you a practical and theoretical understanding of how memory is allocated, managed, and optimized in modern operating systems. Clear, concise, and student-friendly — these notes are a complete resource for mastering OS memory management.