Hard drive: what is it

A hard drive is a device used to store digital content and other data on computers. Every computer has an internal hard drive, but you can also use external hard drives to increase the amount of space on your computer. In this article, we'll take a look at the different types of hard drives and their advantages and disadvantages.

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Backup storage types

All computers require storage media for long-term data storage. These drives are called backup storage, and the computer's random access memory (RAM) is the primary storage.

In general, there are two types of backup storage: hard disk drives (HDDs) and solid state drives (SSDs). SSDs are classified as hard drives, but this is not entirely accurate, and it is important to understand the difference between an HDD and an SSD.

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What is HDD?

HDD is a more traditional type of hard drive.

Hard drives are made up of magnetized metal or glass round platters that rotate at 5,400 to 15,000 rpm. The faster the magnetic disk spins, the faster your computer will be able to access the information on it.
All digital data comes in the form of a binary code - a sequence of ones and zeros that can represent any information. Hard disk read and write heads are used to input these ones and zeros by magnetizing parts of the disk. Each tiny part of the disc has a bit equal to 1 or 0. The head can determine the magnetism of each part by reading information from it. A head that can read data can also write data by changing the magnetization of the bits on the disk.

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With every change, such as saving or deleting a file, the hard disk head adjusts the magnetism of the hard disk accordingly. Think of a turntable with a vinyl disc as a hard disk containing information and a tone arm as heads scanning the information.
Since data is stored on magnets, HDDs are not destroyed when the power is turned off, which means that they retain data even when the computer is turned off.

The maximum capacity of modern internal HDDs can reach 20 TB. Since the advent of SSDs, hard drives have rarely been used as long-term storage devices in a computer, but are still a reliable external storage option.

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What is an SSD?

SSD (Solid State Drives) is a new type of hard drive. This is the preferred type of internal hard drive in most modern laptops. SSDs are also used in all smartphones and tablets.
Solid-state drives use flash memory, as do USB flash drives and memory cards for digital cameras. There are no magnets here; SSDs use semiconductors to store data by changing the electrical state of the trillions of circuits contained within the drive. Since SSDs have no moving parts, they not only run faster (because you don't have to wait for the disks to spin and the heads read information), but also last longer than HDDs.

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SDDs are much more expensive to manufacture, so while they are increasingly being used as the primary hard drives for laptops and high-end PCs, hard drives are still favored by many as a cheaper external option.