A hard disk has the following parameters:
• 6 surfaces
• 20K tracks per surface
• 256 sectors per track
• 512 bytes per sector
• rotational speed 7,200 rpm
a. What is the capacity of the drive?
b. What is the rotational latency?
c. Once a sector has been accessed, what is the rate at which data is read?
a. Capacity = sides × tracks/side × sectors/track × bytes/sector = 
bytes
b. Rotational latency = 1/2 cycle. 7,200 rpm = 120 rps. One revolution = 8.33 ms. latency = 4.17 ms.
c. 512 × 8 bits are read in 8.33ms/256. Data rate = 4096/ 
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