Hard drives explained – 9 things you should know

There are so many different types of hard drives and so many ways to use them that things can get a little confusing! The term hard drive has become a catch-all for the different types of data storage solutions available but is most commonly associated with HDDs and SSDs.

HDD stands for Hard Disk Drive. up until recently, these were the best solution for personal computing when it came to filing storage and storage of your operating system. Hard Disk Drives come in a couple of form factors either 3.5″ or 2.5″ and they utilize the SATA interface to transfer files for your computing needs.

SSD stands for Solid State Drive and these have taken over in most consumer computing applications. They are faster, smaller, and offer accelerated performance for all aspects of computing. They come in the same formats as HDDs as well as the M.2 format which can use either the SATA or an NVMe interface, the latter being a LOT faster.


Where is the hard drive in a computer?

Inside of a computer are a number of components, typically this is a motherboard, graphics card, RAM, a power supply, and disk drives including hard drives. Things like the RAM graphics card and CPU (processor) need to be attached directly to the motherboard itself, this isn’t true for most hard drives, instead, they are connected via a SATA cable. Typically they will be placed and screwed into trays (or bays) at the front of the computer. This keeps all of the SATA connections in one place and is where you are most likely to need a SATA connection for other types of drives like DVD or Bluray.

Modern motherboards come with additional ports directly on them to fit M.2 type hard drives. These can vary in position but you will find them directly on the motherboard themselves and are mounted with a single screw via the NVMe or PCIe interface.

Can hard drives overheat?

It is possible for hard drives to overheat due to poor ventilation, When hard drives overheat they are designed to shut down in order to preserve data. Typically hard drives can withstand higher temperatures than other computer components that will shut down before a hard drive does and often times a hard drive will reduce its speed before shutting off completely in an effort to reduce the running temperature.

It is important to ensure that hard drives have good ventilation and airflow around them to get the best efficiency results from them. All computer components need good ventilation and require cooling during operation.

What are internal hard drives?

Internal hard drives are hard drives that are used inside a computer casing. They are connected directly to the PSU (power supply unit) and the motherboard via a SATA or NVMe interface. They have no additional outer casing or protective casing and often have exposed circuitry. This enables them to be able to shed more heat during an operation inside of the computer case which serves as the protective casing.

Every computer will have at least one hard drive inside of it. A hard drive is a requirement of modern computing systems and is home to the OS (operating system) and is where you store all of your files and folders.

What are external hard drives?

External hard drives are exactly the same as internal hard drives except for one key difference, they are housed in a protective casing. This protective casing serves various functions other than offering the hard drive protection from knocks and drops, it also houses the connection interface and adapts the SATA connection that most hard drives use into a USB, FireWire, Lightning Bolt, or any other type of connection that can be used as an external port on your computer.

Typically external hard drives don’t use the SATA connection that the drive itself is equipped with because SATA connections require a separate power source where connections like USB have that built-in. Because of this most computer cases and laptops only offer USB-type connections for peripheral devices. That said larger desktop-type external hard drives still might require a power source depending on the type of connection it uses.

External hard drives should be used for file storage and not for running programs or operating systems. This is because the way that they are connected is not stable enough to be reliable for running an OS, for example, if you unplugged it while it was running it could completely destroy the OS and mean that your computer needed a complete reinstall.

Do I need to format an external had drive before use?

It is always a good idea to format an external hard drive before using it. This is because although most hard drives will come formatted from the factory the format might not always be suitable for your needs. Mac users will need to format to a different type of file system than Windows users and the same applies to Linux.

Some external hard drives come loaded with a program that can do this for you while others will come preset and empty and some might come with no file system at all. Whatever the case we recommend formatting as follows, for windows use NTFS, for Mac use APFS and for Linux use EXT4. These are the latest files systems for each operating system and will be the most suitable for external hard drives as they offer the best flexibility for files sizes and are more efficient and more compatible than the older systems.

How long do hard drives last?

Hard drives vary in lifespan across the different types and in different applications. The main differences are between SSDs and HDDs (solid state drives and hard disk drives).

SSD hard drives should last for 5 years or more, estimates have been made of them lasting 50 years but the lifespan of an SSD is dependent on its usage and is susceptible to a thing called write wear which. This means that rather than using time as a metric, it is more applicable to calculate the life span of SSDs in TBW (Terabytes Written). This is usually around 150TBW, How long it takes to reach that limit depends on how often and how much data you write to it. If you wrote 30GB of data a day, every day it would last for about 15 years, by which time other points of failure may well have come into play.

HDD hard drives store their data magnetically and this can last a very long time so long as there is no outside influence on the disks. The shortcoming of HDDs are the mechanical components. Where SSDs have no moving parts HDDs have lots of very precise moving parts and are mechanical devices. Most HDD failures are directly connected to mechanical failures, HDDs don’t suffer from write wear like SSDs. Typically you can expect an HDD to last between 8 to 10 years. This is hard to predict for new hard drives but if it has been running for more than 2 years already, the chances it will make it to 8 or 10 are higher. This is due to higher amounts of “early life failures” where minor defects can prevent a drive from functioning properly.

Is hard drive memory?

Hard drives are a type of computer memory known as data storage devices, specifically, they are a type of non-volatile memory. Non-volatile memory means that the memory device can retain stored data without power. Computers use both volatile and non-volatile types of memory to function. RAM is an example of volatile memory. During operation, your computer loads files and information into the RAM (random access memory) from the hard drive in order to have fast access in order to execute any commands the CPU (processor) might have to make.

When you put your computer to sleep, for example, all of the information in the RAM is compressed and is copied to the hard drive as something called page files. This is essentially creating a freeze-frame of everything that is going on on your computer when you press the sleep button. Once your computer is asleep it stops powering most components of the computer, including the RAM and the hard drives. Because the RAM is volatile memory as soon as it loses power it loses all of the data it had stored. The hard drives, however, as non-volatile memory, retain the information as page files. When you wake your computer up it copies the files back to the RAM, decompresses them, and everything functions as it was.

How long does a hard drive last if unused?

Hard drives vary in the amount of time they can last for and the factors that determine that are different for the different types of hard drives, see #7 for more information on that. So with that said there are two ways to look at this question, firstly let’s say the hard drive has never been used, and secondly let’s look at how long a hard drive can last if it hasn’t been plugged in.

The shelf life of a hard drive that has never been used is, in theory, indefinite. There are no components that will degrade without use, perhaps the grease on the spindles of HDDs might degrade but so long as the hard drive is stored well and isn’t knocked then there is no reason an unused hard drive wouldn’t be functional for many years before being turned on for the first time. This applies to SSDs and HDDs but bear in mind that different and fluctuating environmental parameters affect either of them in different ways.

As for a hard drive that has been used and then put in a drawer for a long time then there are limits. HDDs can handle this better than SSDs so long as the HDD is stored in a very safe place and has no chance for the internal mechanisms to be broken while in storage. SDDs don’t have that problem but the nature of how they store data does mean that data can be lost over time. It is a good idea to plug any hard drive in at least once every 6 months to ensure it is still functional and that the data is uncorrupted. You can read more about this here – how long can an SSD store data without power?

How much does a hard drive cost?

Hard drives vary massively in cost. They can be as cheap as $30 and as expensive as $5000 depending on what type and what specs you require. The cheapest hard drives are small-capacity HDDs with low read/write speeds. For example, you can get a 1TB HDD on amazon for $39. At the other end of the spectrum, you can get a 15TB SSD for $5001.

The price you will pay is completely dependent on your needs, when shopping around for a hard drive you should first figure out exactly what interface and form factor you need and then search for the price point based on those specs. For more information check out our buying guide.