Presentation on theme: "Problems in IO & File System CS 1550 Recitation November 4 th /6 th, 2002 The questions in this slide are from Andrew S. Tanenbaum's textbook page 375,"— Presentation transcript:
Problems in IO & File System CS 1550 Recitation November 4 th /6 th, 2002 The questions in this slide are from Andrew S. Tanenbaum's textbook page 375, 450, 451.
CHAP How much cylinder skew is needed for a 7200-rpm disk with a track –to-track seek time of 1 msec? The disk has 200 sectors of 512 bytes each on each track.
CHAP Consider the I-node shown in Fig If it contains 10 direct addresses of 4 bytes each and all disk blocks are 1024 KB, what is the largest possible file?
CHAP A floppy disk has 40 cylinders. A seek takes 6 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 be about 13 cylinders apart, on the average. If, however, the operating system makes an attempt to cluster related blocks, the mean interblock distance can be reduced to 2 cylinders (for example). How long does it take to read a 100-block file in both cases, if the rotational latency is 100 msec and the transfer time 25 msec per block?