Difference between HDD and SSD?


HDD stands for Hard disk drive which uses platters or disk to store data and can read or write data from continuously rotating platters by using read/write head. It consists of a stack of platters that automatically start spinning as soon as computer system switched on, enabling it to store and retrieve a large amount of data from these electromagnetically charged surfaces. These platters are further divided into sectors, tracks, and cylinders.

Cylinder—> Set of Tracks —> Segments of Sectors

Head or an arm located at a fixed point on both sides of platter frequently sense the tracks of the spinning platters as and when it required to read or write data.


Solid state drive, a competitive storage media for HDD which uses a non-volatile storage media technology named NAND flash memory ( A technology that is being used in USB flash drives, SD Cards, and digital camera) . A SSD comprises of a flash controller which responsible for controlling operations related to read or write data and NAND flash memory chip. These are made with FGRs ( floating gate transistors), allowing it to keep retain data which makes it non-volatile. In this, the number of write cycle are limited as the cells where data get stored may wear out due to write operation.

Solid State Drive (SDD) Hard Disk Drive (RDD)
In this, no rotating part is present, instead, semiconductor chips are used namely flash chips to store data. In this type of Storage Device, Data are stored on a rotating platter magnetically.
It uses a non-volatile technology named NAND flash memory which makes it faster and preserves your data for a longer time It is slower than SDD when it comes to read or write data as the transfer rate depends upon the speed of the rotating platter
SDD is more expensive as compared to HDD It is cheaper than SDD
No noise is produced as it doesn't have any moving part for storing data As and when the computer boots up, the platter starts moving as a result noise and vibration are produced
When it comes to capacity SDD falls behind of HDD In terms of Capacity, HDD ranges from 500 GB as the base hard drive capacity. It can hold more data as compare to SDD.

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