How do Hard Drives Work – Everything you need to know

Hard drives are a vital part of some computer systems and several servers. Understanding how hard drives work and how they store & let you access data, can help you better utilize them. 

What is a hard drive

In short, a hard drive is an electromechanical device used for storing and retrieving digital data. 

The first hard drive, the IBM 350 disk storage unit, was released in 1956 and quickly became a popular form of secondary storage for general-purpose computers. 

Hard drives are used to store data, such as backups, but they can also be part of the computer components and be responsible for storing and executing the operating system (OS).

You can find internal hard drives, that are inside your laptop and computer, and external hard drives. Although laptops nowadays are mostly equipped with SSDs, which work differently, most devices have a slot for HDDs. So you can use the hard drive for additional storage space, such as photos, music, applications, and games.

How do hard drives work

Hard drives are composed of many moving parts working together to store and access data. 

At the heart of a hard drive is the spindle motor, which spins magnetic platters at high speeds, allowing it to read and write information onto the disk. 

Around this spindle motor sits an array of electromagnets that move radially in order to read and write data off of the disks as they rotate. 

Data is written onto these platters in concentric circles called tracks, while each track can be further divided into sectors.

To access and store data, the hard drive uses a read/write head that moves across the surface of each disk to collect and write information onto each sector. 

This head is suspended on an actuator arm, which moves across the platter when activated by an electronic signal from the hard drive’s controller board. The controller board also reads how much data is being stored or accessed as it passes over each sector, sending this information back to the computer system. 

The combination of these components makes up how hard drives work, storing vast amounts of data at high speeds for quick retrieval by computers. 

What does the inside of a hard drive look like

Spindle Motor
It controls the HDD spinning speed, measured in revolutions per minute (rpm).

Magnetic Platters

It’s where the data is written and an active moving part of the hard drive.

Read/Write Head 

The head is a “needle” that reads and writes the data on your hard drive. When damaged, you can end up with a dead hard drive.

Actuator Arm 

This part is what keeps the head in place.

Actuator Axis

Holds the actuator arm in place. 

Actuator

It’s an active moving part of the HDD. It is responsible for moving the actuator arm to different positions to read from the disk

Connections

It powers up the hard drive, so it can work and connects it to the motherboard and to the computer.

How does HDD store data?

Data stored on a hard drive is written in the form of 0s and 1s, representing binary code, onto the magnetic platters. The read/write head then stores this data on its surface as it passes over each sector. 

The disk’s spinning speed determines how fast data can be written or retrieved. The faster the spin, the quicker the information travels between the read/write head and disk surface. 

Is hard drive speed important?

Yes, the speed of a hard drive is essential for how quickly data can be accessed by the computer. Hard drives that are faster in terms of how quickly their platters spin can transfer data faster. 

This is especially significant when it comes to applications or games where quick response times are necessary for a smooth experience. 

Additionally, the hard drive speed can affect how quickly files open, how fast downloads occur, and how long boot-up times take (if your device boots from the HDD). 

Overall, the higher the speed of a hard drive, the better overall performance you will get from your computer system. 

How to choose the best HDD?

When shopping for a hard drive, it is critical to consider how you plan to use it. If you need lots of storage space but don’t need the highest speeds, then an HDD would be the better choice. 

For example, if you are storing large amounts of media or gaming files, then a higher-capacity hard drive with faster speeds may be best suited for your needs. 

Ultimately, understanding how hard drives work can help you make an informed decision when deciding which type of storage device is best for your computer system.

So, the best internal hard drive for you depends on your use of it. An external hard drive for photographers and creative professionals has different requirements than for a student that mostly only needs storage for documents.

What is the difference between internal and external hard drives

Internal hard drives are those that are installed inside a computer’s case and connected directly to the motherboard. They are typically used for storing the operating system, applications, and files.

External hard drives, on the other hand, are connected to a computer through USB or another external port. These devices offer an easy backup solution and can be used to store large amounts of data without taking up internal storage space. 

What are the main differences between SSDs and HDDs

There are many differences between SSDs and HDDs: 

• Moving parts: HDDs use spinning platters and an arm with a read/write head, while SSDs have no moving parts. 
• Read/write speed: HDD transfer speeds are typically slower than those of SSDs due to their spinning platter design.
• Cost: HDDs tend to be more affordable compared to SSDs because they contain fewer components and require less complex manufacturing processes. Hard drives cost an average of $0.015 per gigabyte. Meanwhile, SSDs can cost between $0.027 to $3.306 per gigabyte.
• Failure probability: HDDs can suffer from mechanical failure when exposed to strong vibrations or impacts. While the lack of moving parts on SSDs makes them less susceptible to physical damage. Learn more about HDD failures vs. SSD failures.

Hard drive data recovery

Recovering data from a hard drive is simpler than from an SSD. And that’s because of how they store data.

Data recovery services usually don’t have a hard time recovering data from hard drives, regardless of the damaged cause.

SalvageData has over twenty years of HDD recovery service. Trust professionals that think outside the box to restore data even in the most difficult cases.

TL; DR: The hard disk drive (HDD) is an electromechanical data storage device that uses magnetic storage to save and retrieve digital data. It works by writing the data on magnetic platters. Internal HDDs are installed inside a computer’s case and connected directly to the motherboard, while external HDDs are connected through USB. While HDDs have slower transfer speeds and can suffer from physical damage due to their mechanical design, they tend to be more affordable and offer greater storage capacities than many consumer-grade SSDs.