Ever since IBM introduced the hard disk drive back in late 50’s it has been the cornerstone of every desktop or laptop computers for well over half a century.


For the better part of the early 21st century, the traditional mechanical hard disk drive has been the default and often the only storage options for your computing needs. We have come a long way from magnetic tapes and floppy disks.


FeatureSolid State DriveHard Disk Drive
Performance –¬†File Copy / Write SpeedVery FastAverage
Power DrawLessMore
Moving PartsNone2 or More
Noise0 DB27 DB
CapacityNot Larger Than 1 TBTypically Around 500 GB to 2 TB For Laptops
Boot TimeAround 10-13 secondsAround 30 – 45 seconds
Failure RateMean time between failure rate of 2.0 million hoursMean time between failure rate of 1.5 million hours
DurabilityMore DurableLess Durable
File Opening Speed30% Faster than SSDSlower than HDD

The technology is time-tested and works its magic in every household with a computer. Hard disk drives have spinning disks called platters, where you read and write your data.

A Hard Disk Drive is made up of one or more magnetic circular disks(platters), a head used to read and write data on the platters, and a motor that spins the platter and control the actuator arm that moves the head.

Hard Disk drive

It also has an I/O controller and some firmware for the interface with the system. The Platter is divided into concentric circles called tracks, these tracks are divided into sectors.

Every track and sector is given a unique number that is used as an identifier these numbers can be used as an address to organise and retrieve data. The Data is written on the nearest available address. The firmware is used to track where new data is written and identify any anomaly to correct any error.

Hard Disk Drive in computer

Whenever the system wants to retrieve some data or write something the I/O controller will issue a command to the actuator to the desired address and the head gathers the data based on the presence or absence of charge at the given address. If the command is to write or update data the head changes the charge as needed on the specified track and sector.

The problem with traditional hard disk drive is that it has a lot of mechanical parts used for reading and writing data which takes more time for operation than the doing it electronically. These parts can fail from time to time and are susceptible to rough handling such as experiencing a fall.

Also, these drives are heavier and consume a lot of energy. The read and write speed of HDD is considerably lower than a standard SSD. Having said that HDD is a proven technology that has worked well for generations and are quite a lot cheaper than the Solid State Drives currently available in the market.

Solid State drive is a relatively new technology which has grown leaps and bounds in the last few years. From being the talk of the town in research labs to become an option worthwhile to pursue while making buying decisions, it continues to add storage space and get cheaper at the same time.

Solid State drives

A Solid State Drive, unlike traditional HDDs, uses integrated circuit assemblies like the NAND or NOR gates to store data persistently i.e the data is non-volatile and does not vanish when the power is cut off. You can think of a solid state drive as a large flash drive (pen drive) which you use with USB, as they both use the same underlying technology of Gates.

NAND Gates are generally used as they are cheaper to make. Here the floating gate transistors record a charge or the lack of it to store data. These gates are arranged in grids which are further grouped as blocks. The size of these blocks can be different for different cases but remember each row i.e. the grid corresponds to one page.

Like HDD the solid state drive also has a controller that does a lot of work including keeping track of the data and retrieving it.


When the system commands for retrieval or updation of the data the controller looks for the specific address and identifies the charge or lack of it thereof the read the data, updation is more complex in the case of SSD as the whole block needs to be refreshed for making any addition, so data from the old block is copied to other block and then the entire block is rewritten with specified changes after which the copied block is duly erased.

This is done when the drive is idle through a process known as garbage collection. There is a different process called TRIM which is employed, where TRIM tells the SSD which blocks are to be used for rewriting and which ones need to be skipped.

This is done because any SSD has a finite number of blocks and repeated use of the same block may cause wear and tear.

The SSD also use different algorithms to make sure that all blocks approximately get the same read-write operation during a given period. And as these read/write requests require the movement of data from one block to the other SSDs generally make provision for extra blocks, for this process, which can not be accessed by the operating system or by the user. This is done so that there is always enough blocks available for moving data around.

Solid State Drives are relatively new and hence quite expensive. Although a lot of progress has been made with regards to the storage, SSD is still match for HDD. HDD can still hold up to 2.5 times more data than an SSD.

Having said that storage capacity is increasing with every passing moment and the costs are also coming down rapidly. SSD can read/write data a lot faster than an HDD, it has no moving parts and hence more resistant to rough handling and falls.

It uses less energy and hence keeps your computer a hell lot cooler. If you are into gaming or some high-performance computing stuff. SDD is your goto drive for sure.

Hard Disk Drives are Cheaper and gives you more space, but are slower and use more power. SSD, on the other hand, is faster, less prone to wear and tear, energy-efficient but expensive.

So let your needs decide your buying decision. If you are a power user go for SSD, if you don’t worry about a millisecond and are one who does not drop his laptop, HDD will work fine by you. And you can also go for the best of both worlds with a hybrid. SSD for gaming and complex computing and HDD for more mundane stuff. The choice as always is yours.

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