What is a Hard Disk?
A hard disk is also known as Hard Disk Drive (HDD), hard drive and fixed disk. It is a non-volatile storage device used to store data permanently and retrieve it any time. This device is characterised as non-volatile because it retains data even when the power supply is cut off.
Hard disk is a secondary storage device that is present inside the computer and is connected to the motherboard through data cables. It contains one or more circular disks that rotate and store the data using magnetic storage.
Types of Hard Disks
There are two types of hard disks: HDD and SSD.
Hard Disk Drive (HDD)
HDDs have been around for more than 50 years. They have disks that spin to store data magnetically. HDDS contain several aluminium plates whose rotation performs reading and writing operations. The sensing head is located at a few nanometers. The speed of the plates can be as high as 15,000 revolutions per minute that leads to common noise during operation.
The popularity of these drives is due to the amount of space (up to 4TB on a single HDD), high reliability and stability.
HDDs have lesser speed than Solid State Drives (SSDs) and are available at cheaper rates and more storage capacities than SSDs.
Solid State Drive (SSD)
It is the latest variation of hard disks and therefore, is better than the previous one. Flash memory technology is used to store data in an SSD with an extremely fast data transfer speed. It is also more expensive than an HDD.
It is known as a solid state device because it is stronger than an electromechanical drive.
SSDs make use of memory chips and are completely silent since they don’t have any rotating elements. Their size and power consumption is lesser than that of HDDs. Reading and writing operations are performed faster in SSDs (i.e., files are opened, saved and deleted faster).
This drive is made of two major components: flash controller and NAND flash memory chips.
The relation of the data transfer rate to the size of the transmitted data block is defined by IOPS (Input/Output Operations Per Second). In SSDs, this rate is more than 8000 IOPS, while it is about 80-100 IOPS in HDD.
The latest laptops and PCs use SSDs because of their advanced properties and performance.
SSDs are further divided into: mSATA, M.2, NVMe.
mSATA SSD
This type of SSD is also known as Mini-SATA. It works on SATA connection for power and data transfer. It is commonly used in notebooks, laptops, small form factor PCs, etc.
M.2 SSD
M.2 SATA refers to the form factor as well as connector type. It is available as a bare circuit board and comes in various sizes. The versatility of m.2 SSDs makes them ideal for portable devices such as ultrabooks and tablets.
NVMe
M.2 also supports NVMe, which provides a much better performance. NVMe promises lower latency by operating with higher efficiency, working with Solid State’s parallelization abilities by being able to run more than two thousand times more commands to or from the drive than compared to a drive on the AHCI controller.
Differences between Desktop and Laptop HDD
Although both Desktop HDD and Laptop HDD have the same functions, they differ in terms of performance and specifications.
Desktop HDD | Laptop HDD | |
Speed | 7200 rpm | 5400 rpm |
Size | 3.5 inches | 2.5 inches |
Storage | More than 3 TB | 1 TB |
Performance | Loading time of 30-50 seconds | Loading time of 1-1.5 minutes |