Find the number of disk blocks in a given hard disk in dbms data storage

Find the number of disk blocks in a given hard disk in DBMS data storage

Question:

Following are the characteristics of a hard disk; Sector size of 512 bytes, 16 sectors per track, 16384 tracks per surface, 4 double sided platter, and 4096 bytes per block. Find the number of blocks in that disk.

Solution:

Let us find the total capacity of given disk in bytes.

A track has 16 sectors each of which is 512 bytes in size.

Capacity of a track      = Sector size * Number of sectors

= 512 * 16 = 8192 bytes.

There are 16384 tracks in a surface of a disk platter.

Capacity of one surface of disk platter = No. of tracks * Capacity of a track

                                      = 16384 * 8192 = 134217728 bytes

Capacity of one double sided platter = 134217728 * 2 (2 sides per disk)

                                                                   = 268435456 bytes

There are 4 double sided platters.

Capacity of the hard disk = Capacity of one disk platter * No. of disk platters

                                                = 268435456 * 4

                                                = 1073741824 bytes

It is given that the block size is 4096.

The number of blocks = (capacity of the hard disk) / (block size)

                                      = 1073741824/4096 = 262144 blocks

The hard disk with the given characteristics will have 262144 blocks.

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