Cache replacement policies

Duration: 2 min

This video lesson is available to enrolled students.

Return to /learn/ISRO/digital-electronics/cache-memory-organization/cache-replacement-policies-miss-types/asset-cache-replacement-policies after enrolling

Inside: a video lesson and guided study material.

Module outline

  1. About Course: About the Course
  2. General Aptitude & Reasoning: Number System, Percentage, Ratio and Proportion (Ratios), Average, Profit and Loss, Simple Interest and Compound Interest, Time and Work, Speed Time and Distance, Mixture and Alligation, Data Interpretation, Algebra, Probability, Permutation and Combination, Venn Diagram, HCF LCM, Divisibility Rules, Age Problems, Pipe and Cistern, Partnership, Linear Algebra, Sequence and Series (Series), Statistics, Powers and Exponents (Surds and Indices), Arithmetic, Mensuration and Geometry, Calculus, Trigonometry, Vectors, Speed Mathematics and Basic Mathematics, Non Verbal Reasoning (Spatial Aptitude) (Spatial Reasoning) (Visual Reasoning), Analogy, Series (Number and Letter Series) (Numerical Relations and Reasoning), Puzzle Solving (Puzzles), Syllogisms, Deductive and Inductive Reasoning (Logical Deduction and Induction) (Prepositional Reasoning), Calendar, Seating Arrangements, Coding Decoding, Blood Relations, Directions (Direction Test), Clock, Analytical Reasoning (Counting Figures Reasoning), Ranking, Order and Sequence, Logical Sequence Of Words, Inequality, Data Sufficiency, Cubes & Dices
  3. Computer Networks & Cybersecurity: Introduction to CN, Data Communication, DLL: Access Control, DLL: Flow Control, DLL: Error Control, DLL: Framing, Data Link Layer - Ethernet, Net Layer: IPv4 & Proto, Net Layer: IP Addressing, Net Layer:Routing Protocol, Transport Layer Services, TL: Congestion & UDP, Application Layer, Hardware Basics, Network Security
  4. Programming, Data Structures & Algorithms: C Fundamentals, Control Flow, Functions, Arrays & Pointers, Storage Classes, Structures & Enums, DMA, Macros, Scoping & File Handling, OOPS with C++, Introduction to DS, Array, Stack, Queue, Linked List, Tree, Graphs, Hashing, Algorithm Analysis, Time Complexity Analysis, Sorting Algorithms, Greedy Algorithms, Dynamic Programming, Minimum Spanning Trees, Shortest Path Algos, Advanced Algorithms
  5. AI, Machine Learning, Big Data & Cloud: Emerging Tech Trends, Artificial Intelligence, Big Data Systems, Approaches to AI, Search Algorithms, Knowledge Representation, Cloud Computing
  6. Digital Logic & Computer Organization: Digital Systems & Boolean Basics, Logic Gates & Hardware, Boolean Expression, Boolean Minimization, Combinational Circuit, Sequential Circuits, Number System, Number Representation, Basics of COA, Floating Point Rep, Cache Memory Organization, Input Output Organisation, Pipelining, Instr Formats & Modes, Register Transfer and Microoperations, Control Unit Design, Programming the Basic Computer
  7. TOC & Compiler: Introduction to TOC, Deterministic FA (DFA), Non-Deterministic FA, Regular Expressions, Grammar, Regular Language Properties, Moore & Mealy Machines, Pushdown Automata & CFG, Turing Machines, Complexity Theory, Intro to Compilers, Lexical Analysis, Grammar & CFG, Syntax Analysis: Top-Down, Syntax Analysis: Bottom-Up, Semantic Analysis & SDT, Intermediate Code Gen, Code Optimization, Run Time Environment
  8. Discrete Mathematics: Set Theory, Relations, Functions, Graph Theory, Group Theory, Propositional and Predicate Logic
  9. Operating System: Introduction to OS, Process Management, CPU Scheduling, Process Synchronization, Threads & Process Creation, Deadlock, Memory Management, Virtual Memory, Disc Scheduling, File Management, Unix OS, Linux OS, Distributed Systems
  10. Software Engineering: Fundamentals of Software Engineering, Software Requirements and Quality Assurance, Software Design, Estimation and Metrics, Software Testing, Software Maintenance and Configuration Management, Object Oriented Technology, HTML Basics, JavaScript-Basics, Java, XML
  11. Database Management System: Basics of DBMS, ER Diagram, Relational Model & Functional Dependencies, Keys & Integrity Constraints, Normalization (1NF - BCNF), Decomposition Properties & 4NF, File Organization & Indexing, Relational Algebra, SQL, Relational Calculus, Transaction Management, Concurrency Control, Database Recovery, Data Warehousing & Mining, Enhanced Data Models, NoSQL
  12. Other Recurring CS Topics: Basics of Computer Graphics, 2-D Geometrical Transforms and Viewing, Multimedia
  13. Live Classes: ISRO Live classes
  14. Full Mock Test:
AI summary & chapters

AI Summary

An AI-generated summary of this video lecture.

This lecture segment introduces the fundamental concept of Cache Replacement Policies within computer architecture. The instructor explains a critical distinction between cache mapping techniques. He states that direct mapped caches do not require replacement policies because the position of each block is predetermined by the memory address. In contrast, fully associative and set associative caches necessitate specific policies. The core problem addressed is the scenario where a new block is brought into the cache, but all available positions that it may occupy are full. In this specific situation, the controller needs to decide which of the old blocks it can overwrite to accommodate the new data.

Chapters

  1. 0:00 – 2:00 00:00-02:00

    The video begins with a slide titled 'Cache Replacement Policies' displayed prominently. The first bullet point states: 'In direct mapped cache, the position of each block is predetermined hence no replacement policy exists.' The second point clarifies: 'In fully associative and set associative caches there exists policies.' The third point sets the context for the lecture: 'When a new block is brought into the cache and all the positions that it may occupy are full, then the controller needs to decide which of the old blocks it can overwrite.' The instructor verbally reinforces these points, establishing the necessity of replacement algorithms in specific cache mapping techniques where flexibility exists.

  2. 2:00 – 2:28 02:00-02:28

    The instructor begins a visual demonstration to illustrate the replacement process described in the text. He draws a vertical rectangle on the screen, representing a cache set or a specific location within the cache structure. Inside the rectangle, he draws horizontal lines to represent existing blocks occupying the space. He then draws a circle to the right, symbolizing a new block arriving. An arrow is drawn from the circle towards the top of the rectangle, indicating the new block's attempt to enter. Finally, a question mark is drawn next to the arrow, visually representing the critical decision the controller must make: determining which specific old block to evict.

The lesson progresses from theoretical definitions to a visual representation of the problem. It establishes that replacement policies are only relevant when there is a choice of location (associative mapping). The drawing serves as a precursor to specific algorithms like LRU or FIFO, which will likely be discussed next to solve the 'question mark' problem of block eviction. This sets the stage for understanding how hardware manages limited cache space efficiently by making intelligent decisions about data retention versus replacement.

Loading lesson…