作者x3795566 (冀忆)
看板Grad-ProbAsk
标题[理工] OS-file system
时间Mon Jun 8 00:16:09 2009
以下为题目
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.
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?
我看超久的还是不太懂怎麽写 冏rz
希望有高手可以解答
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