UGC NET CSE | December 2018 | Part 2 | Question: 18

Question

Consider a disk pack with $32$ surfaces, $64$ tracks and $512$ sectors per pack. $256$ bytes of data are stored in a bit serial manner in a sector. The number of bits required to specify a particular sector in the disk is

• A. $18$
• B. $19$
• C. $20$
• D. $22$

Comments

But it is mentioned 512 sectors per pack.

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yes printing mistake most probably :/

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Thanks

Answer 1

Total sectors = No.of surfaces * no.of tracks per surfaces * number of sectors per tracks = 32 * 64 * 512 = $2^5 . 2^6 . 2^9 = 2^{20}$.

∴ No.of bits required to identify each sector = 20 bits

Answer 2

Total number of sectors = 512*64*32 = (2^9)*(2^6)*(2^5) = 2^20

So 20 bits are required to specify a track in the disk.

Option (C).

Answer 3

To calculates the number of bits required to access  sector we need to know total number of sector

Total number of sector =32 Surface * 64 Track * 512 Sector

                                     = 2^5 * 2^6  * 2^9

                                      2^20

No. of bits required to identify each sector=20 bits

So option C is correct  answer.

Answer 4

Surfaces=2^5, Tracks=2^6,  Sectors=2^9

So, no of sectors= 2^(5+6+9)=2^20

option A