A hard drive is a non-volatile hardware component on a computer that acts as the storage for all digital content. It holds program files, documents, pictures, videos, music, and more.

The non-volatile nature of hard drives means they don’t lose data, even if power is lost. Due to this, they help computers store files and other data for a long time – as long as they don’t get damaged or corrupted.

Since the first release of hard drives by IBM in 1956, hard drives have evolved from being the size of a refrigerator and having a storage capacity of just 5MB to ones that are pocket-sized and have up to 4 TB of storage capacity.

In this article, I will cover the different types of hard drives so you can choose the best for your computer.

But firstly, let's look at interfaces – the connecting part between the computer and the hard drive.

Types of Interfaces

  • Parallel Advanced Technology Attachment (PATA)
  • Serial Advanced Technology Attachment (SATA)
  • Small Computer System Interface (SCSI)
  • NVMe (Non-volatile Memory Express)

These names come from the way they connect to the computer. So, there are PATA hard drives, SATA hard drives, SCSI hard drives, and NVMe drives.

In this article, I’m now going to elaborate on each of these interfaces and types of hard drives as concisely as possible.

Parallel Advanced Technology Attachment (PATA)

The PATA interfaces were first introduced to the market by Compaq and Western Digital in 1986. They can have up to 80GB capacity and transfer data as fast as 133 MB/S.

They were named Parallel Advanced Technology Attachment because they use a parallel ATA interface to connect to the computer. Apart from PATA, they are also called Integrated Drive Electronics (IDE) and Enhanced Integrated Drive Electronics (EIDE).

PATA interfaces are made of mechanical moving parts and are based on parallel signaling technology – meaning they transmit multiple bits of data simultaneously.

Serial Advanced Technology Attachment (SATA)

In recent times, a lot of desktop and laptop computers have gotten SATA interfaces because they have superseded PATA interfaces in size, power consumption, and even better pricing.

The mode of connection to a computer remains the same as PATA, but instead of parallel signaling technology for data transmission, they use serial signaling technology. This means that they transfer data one bit at a time.

A notable advantage SATA interfaces have over PATA interfaces is the transmission of data at a rate of 150 – 300 MB/S. In addition, they have thinner cables and a cable limit of 1 meter.

Small Computer System Interface (SCSI)

SCSI interface is an upgrade over SATA and PATA interfaces for many reasons such as round-the-clock operations, speed, storage, and several others.

For connection, SCSI hard drives use a small computer system interface – which is a standard for connecting peripheral devices such as printers, scanners, and others.

Best of all, they allow the connection of peripheral devices such as printers, scanners, and other hard drives. In addition, they transmit data at 320 MB/S and you can connect them internally or externally.

Connections through SCSI on personal computers have now been replaced by the Universal Serial BUS (USB). This means that SCSI is no longer used as consumer hardware.

NVMe (Non-volatile Memory Express)

NVMe interface is a revolution. It is built for high demanding and computing-intensive tasks So, it is an upgrade over the interfaces already discussed.

Because of its high performance and scalability, you'll find it mostly in data centers and newer computers. There are now SSDs using the NVMe interface.

Its many advantages over other interfaces are:

  • lower power consumption
  • multiple command queues
  • reduced latency and input/output overhead – leading to better performance
  • utilization of CPU to full potential

One of the disadvantages of NVMe interfaces is that they're more expensive than other interfaces.

Types of Hard Drives

Currently, there are two common types of hard drive:

  • Hard Disk Drive (HDD)
  • Solid State Drive (SSD)

A hard drive utilizes any of the interfaces such as PATA, SATA, SCSI. Today, there are SSDs that utilize the NVMe interface.

Let's look at the two types of hard drives in detail.

Hard Disk Drive (HDD)

Hard disk drives are not that new and you will find them installed in older computers. They consist of a moving part that rotates during reading and writing operations, so they usually make noise.

These days, you may not see many newer desktop and laptop computers with hard disk drives, but they remain popular because of their storage space. 16 GB, 32 GB, and 64 GB are the lowest you can find out there. There are 500 GB, 1 TB, 2TB, and more than 4 TB hard drives.

This enormous storage space is the reason hard disk drives may go nowhere any time soon. There are even external hard disk drives you can use to backup your files.

Solid State Drive (SSD)

SSD hard drives are one of the latest hard drive technologies at the time of writing this article. Most newer computers have SSDs instead of HDDs.

Unlike the hard drive technologies before SSD drives, they don’t consist of moving parts and they don’t use magnetism for storing data. So, they don't make noise like hard disk drives (HDDs).

Instead, they use integrated circuits (ICs) just like third-generation computers. This makes them more durable, faster, and less prone to damage and corruption.

SSD hard drives have a notable advantage of transferring data at speed of 550 MB/S and allow faster boot times than the types of hard drives before them.

Solid state drives also have enormous sizes, but they are very expensive when compared to hard disk drives.


This article explained what different types of hard drives are and how they work, so you can learn more about hard drives and choose the best one for your needs.

From PATA to SATA, SCSI and NVMe, hard drive interfaces continue to evolve and research to make better ones is ongoing.

There is a new variation of SSD hard drives called NVMe (Non-volatile Memory Express) SSDs that has the capacity to transfer data as fast as 3.5 GB/S. This makes them the best choice for video editing and high-resolution gaming, though they require more power than the actual SSDs.

Thank you for reading.

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