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# TUTORIAL 1

TUTORIAL 1. FIFO vs LRU. First-in first-out (FIFO) policy: a page replacement policy that removes from main memory the pages that were brought in first. *KEY = Identify what are FIRST PAGE REQUEST for in and out?.

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## TUTORIAL 1

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1. TUTORIAL 1 FIFO vs LRU

2. First-in first-out (FIFO) policy: a page replacement policy that removes from main memory the pages that were brought in first. *KEY = Identify what are FIRST PAGE REQUEST for in and out? • Least recently used (LRU) policy: a page-replacement policy that removes from main memory the pages that show the least amount of recent activity. *KEY=Identify what are the LATEST PAGE to standby for out? DEFINITION

3. Identify how much PAGE FRAMES are available. • Identify how much JOB PAGES. • Identify job to process (PAGE REQUESTED). • Identify PAGE swapped IN to and OUT of memory (from Page Frames) • Marks each interrupt with an asterisk. • Count the number of page interrupts. • Compute the FAILURE rate and the SUCCESS rate. FIFO PROCEDURE

4. Example form Textbook; Figure 3.8

5. PAGE FRAMES = 2 • JOB PAGES = 4 (A,B,C,D) • Arrangement PAGE REQUESTED = A, B, A, C, A, B, D, B, A, C, D So, Total number Page Requested are 11. QUESTION : Using the FIFO page removal algorithm, does a page trace analysis indicating page faults with asterisks (*). Then compute the failure and success ratios. Identify Requirement

6. 1 2 3 4 5 6 7 8 9 10 11 A B A C A B D B A C D * * * * * * * * * A A A C C B B B A A D FIFO1 FIFO1 FIFO1 FIFO1 FIFO1 B B B A A D D D C C FIFO2 FIFO2 FIFO2 FIFO2 Answer/Explanation FIFO