Different types of hard disks for storing vital information
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Different types of hard disks for storing vital information

Like most things in the computer world the hard drive was also introduced to the world by IBM, the first hard drive released by IBM was the IBM model 350 disk file. The hard drive had 50-24 inch disks which were contained inside a cabinet that was as big as a cupboard and with all that it was able to store around 5MB of data.

From their hard drives evolved to a point where they can be accommodated inside a desktop and thanks to the constant developments and innovations in the field of data storage, we have reached a point where we can buy a 3.5inch HDD with 1.5TB storage space.

A hard drive or HD is a non-volatile storage device that is usually installed internally in a computer. Computers use hard drives to save and retrieve data that are required for future reference. Since these internal hard disks are non-volatile, they are able to retain information even when they are not having any power as long as the hard drive is intact the data stored in it will remain safe.

How does a computer hard disk work?

Pc hard disks or laptop HDD have a spinning wheel with a thin magnetic coating inside, when data is being copied into the hard drive the head will move over the platter writing 0s and 1s in tiny areas of magnetic north and south on the platter.

In a time of the data retrieval, the head will go to the same spot, and from the areas separated as magnetic north and south will deduce the 0s and 1s. A modern hard drive can store over a trillion 0/1 bits per platter.

Different types of hard disk interfaces:

An internal hard disk is connected to a computer by means of a data cable that relies on IDE or SATA technology to the motherboard and power supply.

PATA hard drives-

These were one of the first types of hard drives to arrive in the market, these hard disks relied on the Parallel interface standard invented by Western Digital back in 1986. Both the IDE(integrated drive electronics) and EIDE(enhanced integrated drive electronic) drives fall into this category.

In the drives using the parallel interface standard the data transfer was up to 133mb/s and at max 2 devices can be connected to the drive channel at a time. Like most hard disks PATA hard drives also make use of the principle of magnetism to store the data and the internal structure is made of mechanical moving parts.

SATA hard drives-

The SATA hard drive came after the PATA, what made them different from the PATA hard drives was their interface only as they still used the same method to connect to computers. Since the SATA pc hard disks were using serial technology they were able to transfer data at faster rates than PATA hard drives. And the SATA hard drives will only require 250mv for their operation whereas the PATA hard drives will consume somewhere around 5V for their operation.

Types of technology used in hard drives:

The types of technology currently used in computer hard disks fall into 3 categories, solid-state drives, magnetic drives, and hybrid drives.


SSDs have started to replace HDDs owing to the advantage they have over the HDDs. SSD hard disks are one of the fastest types of hard drives currently in the market. The SSD hard drive will allow us to access the data in a fraction of a millisecond which in turn will result in shorter boot times.

What makes the SSD hard disk technology different from other hard disks is that they don't have any moving parts inside them and like previous models of computer hard disks they didn't rely on magnetism to store data. The SSD hard drive relies on flash memory technology, and instead of using motors and disks with magnetic coatings, they rely on integrated circuits and solid-state electronics to store data.

So compared to magnetic hard drives the SSD hard drives are faster, more durable, and consume less power. Most people are preferring SSD hard disks for laptops and recently companies like SanDisk, Samsung have started to offer external SSD hard drives.

Magnetic Hard drives-

Magnetic hard drives rely on rotating magnetic disks called platters with magnetic coating and motors to move the head to read and write the data into the hard drives.

The magnetic hard drives as the name suggest relying on the principles of magnetism to read and write the data. The data is stored in circular regions of the disk that are known as tracks which in turn are divided into sectors that contain blocks of data. Despite them being slower than SSD hard disks and consuming more power, people still buy them as they are cheaper and have higher capacity compared to SSDs.

Most of the internal hard disk or desktop drive and the external hard disk are using magnetic hard drives to store data.

Hybrid hard drives-

Hybrid hard drives are types of hard drives that make use of both platters and flash memory. The hybrid hard drives are the perfect example of the term “best of both worlds. The hybrid hard drive is a kind of storage device that combines the faster storage capabilities of an SSD hard disk with the higher storage capacity of magnetic hard drives.

Many power users and gamers are using both HDD and SSD, and even in some cases even an external HDD or USB hard disk. They will be using the SSD hard drive for storing system files, programs, and application data in order to ensure the smooth running of their computers whereas the magnetic external hard drive or external HDD will be used for media, photo collections, etc and those that don't need files that don't need to be accessed quickly.

The hybrid hard drive is magnetic drives with SSD storage, to the OS the hard drive will appear as a single drive. These kinds of hard drives will come with a pre-installed firmware that decides what will be and what will not be stored in the SDD. The SSD portion of the hard drive will act as a cache and frequently accessed files like the OS and all will be stored in the SSD hard drive, despite it being a cache memory it's non-volatile i.e. the data stored will persist across reboots.

Internal vs External Confusion-

There isn't much difference between an external hard disk drive and an internal hard disk while an internal drive is built into the desktop or laptop while an external HDD is not. A computer can function without an external pc hard disk or laptop HDD but it will not be able to function without an internal pc hard disk/desktop drive.

Most people use a portable hard disk to back up their data as part of a contingency plan and also to store those files which they don't have the use of on a frequent basis.

Conclusion: SSD vs HDD vs Hybrid

One of the frequently asked queries in almost all of the popular hardware sites is that which is the best option is to have a computer running on hybrid HDD or a combination of SSD and mechanical HDD. According to hardware experts, it's better to go with a combination of SSD plus mechanical HDD for either desktop or laptops.