Concern a disk with a sector size of 512 bytes, 2000 tracks per surface, 50…
2020
Concern a disk with a sector size of 512 bytes, 2000 tracks per surface, 50 sectors per track, five double-sided platters, and average seek time of 10 milliseconds with rotational speed of 5400 rpm.
If one track of data can be transferred per revolution, then what is the data transfer rate?
- A.
2,850 KBytes/second
- B.
4,500 KBytes/second
- C.
5,700 KBytes/second
- D.
2,250 KBytes/second
Attempted by 64 students.
Show answer & explanation
Correct answer: D
Step-by-step solution:
Compute bytes per track: 50 sectors × 512 bytes = 25,600 bytes
Express in kilobytes (1 KB = 1024 bytes): 25,600 ÷ 1024 = 25 KB
Interpretation of "one track per revolution": during each revolution the drive can transfer one track (25 KB) from the active surface.
Use a typical rotational speed to get revolutions per second. A common disk speed is 5,400 rpm which equals 5,400 ÷ 60 = 90 revolutions per second
Compute transfer rate: 25 KB × 90 rev/s = 2,250 KB/s
Final answer: 2,250 KBytes/second.
Note: The average seek time (10 ms) affects positioning latency between tracks, not the sustained per-revolution transfer rate used above. Also, although there are multiple platter surfaces physically, the calculation assumes one surface (one head) is read at a time; multiplying by all surfaces would be incorrect unless the device can read all surfaces simultaneously.
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