In the ever-evolving landscape of computer science, a strong command over data structures and file organization is essential for designing efficient, reliable, and scalable software systems. These concepts form the backbone of algorithm development and memory management, making them critical for students and professionals alike. To support learners in mastering these foundational topics, "IGNOU BCA Data and File Structure Previous Year Unsolved Papers MCS 021" offers a thoughtfully curated collection of unsolved question papers from previous IGNOU examinations. This book is designed to encourage deep conceptual understanding and promote independent problem-solving. The questions span a wide array of topics including arrays, linked lists, stacks, queues, trees, graphs, hashing techniques, and file organization methods such as sequential, indexed, and direct access. Presented in an unsolved format, these papers challenge students to apply theoretical knowledge to practical problems, strengthening analytical skills and boosting exam preparedness. We hope this resource becomes a trusted companion in your academic journey, equipping you with the tools needed to succeed in both assessments and real-world computing challenges.