Exercise 1: Hard Disks (5 Points)
Suppose we have a hard disk with sectors of 512 bytes. Each track has 512 sectors, each platter surface has 4096 tracks, and the disk has 5 double-sided platters. The average seek time is 10 ms.
a) How many bytes can be stored on the hard disk?
b) What is the total number of cylinders?
c) If the hard disk rotates with 7200 rpm (revolutions per minute), what is the maximum andthe average rotation delay (in ms)?
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Exercise 2: Parities (3 Points)
Assume that we are using a RAID-3 system with four hard disks. The following eight bits are stored on the first three data disks.
Disk 1: 10101010, Disk 2: 11001100, Disk 3: 11111111
a) How will the parity sequence look like on the fourth disk?
b) If Disk 2 gets damaged, how can the lost eight bits be restored?
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Exercise 3: Creating and Reading Files with Java (7 Points)
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Please download and unzip the file assignment01.zip from the course website.
• Implement the methods IO#create() and IO#read(). Write the most efficient code you can think of!
• Did you expect the resulting performance? If yes/no, why (not)? Write a couple of sentences to explain the (sub-)optimal performance of your implementation.
