※ 引述《x3795566 (冀憶)》之銘言： : 以下為題目 : A disk has 4000 cylinders, each with 8 tracks of 512 blocks. : A seek takes 1 msec per cylinder moved. : If no attempt is made to put the blocks of a file close to each other, two : blocks that are logically consecutive : (i.e., follow one another in the file) will require an average seek, which : takes 5 msec. 5 msec + (10 msec + 0.02 msec) = 15.02 msec(access time per block) 15.02 msec * 100 = 1.502 sec (100 blocks access time) : If, however, the operating system makes an attempt to cluster related blocks : , the mean interblock distance can be reduced to 2 cylinders and the seek : time reduced to 100 microsec. How long does it take to read a 100 block file : in both cases, if the rotational latency is 10 msec and the transfer time : is 20 microsec per block? (0.1 msec * 2) + (10 msec + 0.02 msec) = 10.22 msec (access time per block) 10.22 msec * 100 = 1.022 sec (100 blocks access time) : 我看超久的還是不太懂怎麼寫 冏rz : 希望有高手可以解答 -- --

※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 140.113.235.115 ※ 編輯: svanavs 來自: 140.113.235.115 (06/08 14:51)