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DRAFT y +1/1/60+ y Student ID (Matricola) 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 Computing Infrastructures Course 095897 P. Cremonesi, M. Gribaudo 13-07-2015 Last Name / Cognome: ................................................................. First Name / Nome: ................................................................. Answers must be given exclusively on the answer sheet (last sheet): DO NOT FILL ANY BOX IN THIS SHEET Students must use pen (black or blue) to mark answers (no pencil). Students are permitted to use a non-programmable calculator. Students are NOT permitted to copy anyone else’s answers, pass notes amongst themselves, or engage in other forms of misconduct at any time during the exam. Students are NOT permitted to use mobile phones and similar connected devices. Scores: correct answers +1 point, unanswered questions 0 points, wrong answers -0.333 points. Reserve questions must NOT be answered, unless explicitly stated during the exam. y For your examination, preferably print documents compiled from auto-multiple-choice. y DRAFT y +1/2/59+ y Disks An HDD has a rotational speed of6000 RP M, an average seek time of6 ms, a controller overhead of 0.2 ms, and a transfer rate of50 M B/s. Block size is4 KB. Question 1 Which is the average latency of the disk? A 6 ms B 5 ms C 10 ms D 3 ms SOLUTION: Tlat = (60000/6000)/2 = 5 ms. Question 2 Which is the transfer time for a block? A 0.078125 ms B 0.390625 ms C 0.019531 ms D 0.78125 ms SOLUTION: Ttr = 4/(50 · 1024) · 1000 = 0 .078125 ms. Question 3 Which is the average access time for a block? A 11.078125 ms B 11.278125 ms C 11.219531 ms D 16.27812 ms SOLUTION: TAcc = Tseek + Tlat + Tctrl + Ttr = 6 + 5 + 0 .078125 + 0.2 = 11…