There are many different types of components, devices and even entire systems that can be used to store your data. We’ll take a look at the most common types of storage and help you understand everything ranging from HDD, SSD, PCIeSSD, NAS, SAN and more!

Computer hard disk drive
Hard Disk Drive


Storage components are used by your computer as a location to store bulk data until it’s required. The most common form of storage is an internal disk drive which can retain/store information even when it is powered off.

The storage device on your computer is required to hold everything from the everyday documents you use to the system files required by the operating system. Your computer’s processor accesses required data on your storage device and loads into RAM to allow rapid access to the operating system, applications and your files.


There are three main categories of storage:

Internal storage

Storage devices that exist inside your computer/laptop.

In consumer computers, there are typically 2 main kinds of storage devices available:

  • Hard Disk Drive (HDD) – most computers use a HDD storage device, where spinning re-writable magnetic disks are used to store data.
  • Solid State Drive (SSD) – considered a ‘newer’ technology than HDDs, SSDs have no moving parts, are more reliable and significantly faster. They run off ‘flash’ memory chips rather than the spinning metal disk found in HDDs.
Solid state drive. These are lighter in weight, physically smaller, and more robust than hard disk drives.

External storage

Storage devices housed outside your computer/laptop.

The most common example for this category is a external USB hard drive. These are usually just a regular HDD inside of a portable enclosure with external USB connectivity. You may sometimes find external storage devices which connect via eSATA (faster) or Firewire (older). These are alternate connection methods which only some computers support.

Also falling into this category are what I refer to as USB sticks. These are a small amount of flash based memory packaged into a very small device with USB connectivity. They act much like an external USB hard drive does except with a different type of storage. These devices are refereed to by many different names such as: flash drive, thumb drive, Pen drive, jump drive, dongle, clip drive and probably a few others.

Network storage

Dedicated storage devices located on your network.

Network storage devices are systems which house multiple HDDs or SSDs and provide shared access to the data to multiple computers over a network. These devices have their own proprietary operating systems which manage the hard disks and provide a means of managing and sharing the data. They also use technologies such as RAID (redundant array of independent disks) which essentially group physical HDDs together and allow them to appear as one big single disk while providing tolerances to hard drive failures and improving performance.

A few examples of network storage:

NAS – Network Attached Storage: A NAS is the most common type of network storage available and can be found in a huge range of sizes and capabilities. Many home users choose smaller 2 or 5 bay NAS systems for storing their data. A 2 bay NAS can only accommodate up to 2 internal HDDs which will limit the total mount of storage space available. It’s important to chose a NAS that can house enough HDDs to store all of your data while still providing redundancy for hard disk failures.

SAN – Storage Area Network: SAN is a concept which you’ll only see in the corporate world and refers to a large storage system used by server infrastructure. The SAN is made of up of several components, namely the storage switches, underlying network hardware and storage array. The storage array is somewhat similar to a NAS, it’s the actual storage device which contains HDDs and SSDs. They offer a very high level of redundancy with multiple power supplies, multiple network ports and multiple controllers (the main system containing the CPU and RAM).  More often than not when you hear someone say SAN, they’re usually referring to the storage array itself.

Selection Considerations

The main selection criteria when it comes to storage devices is the size (how much data it can hold). However, speed is also an important characteristic that many should consider.

  • Storage capacity (size) – The size of your storage device will determine how much data you can put on it. You’ll notice capacities measured in Gigabytes (GB) and Terrabytes (TB) such as 250GB or 2 TB for example. Technically, these may more accurately be specified in Gibibytes and Tebibytes but that’s a story for another time.
  • Speed – The type of storage device can dramatically influence the speed at which data can be accessed, due to a number factors.
  • Connection type – The type of connection of the storage drive to your motherboard can affect the speed of read/write operations when you are accessing the drive, and this will impact on performance. SATA2, SATA3, PCIe or M.2 are the connection types at present.

Further selection considerations include:

  • Physical Size – The physical size of the device can impact whether it can fit inside your system. Most common sizes are 3.5 inch and 2.5 inch.
  • Noise – HDDs will always give off some noise due to the spinning disk. SSDs are silent.
  • Reliability/Durability – Moving parts can make a HDD less reliable than an SSD. HDDs are generally seen to be less durable especially when being moved around in a laptop.
  • Failure Modes – HDDs will often give some indication that they will soon fail (e.g. noise). While if an SSD fails, it can do so without warning.
  • Recoverability – Many methods have been tried and tested that allow data to be recovered from failed HDDs with a high success rate, but recovering data from a failed SSD is a new challenge to the industry.
  • Power Consumption & Heat – HDDs will typically use more power and generate more heat than an SSD.


Connection Types

The way your storage device connects to your motherboard can greatly affect its performance. A higher specced connection type can mean more data throughput, which means faster read/write times and can give a noticeable speed increase from the end user’s perspective.

When looking at connecting up a hard disk drive or solid state drive, you will generally need to consider connections for both power and data. This means you will always have 2 cables to plug into a drive – one for power, and one for data.

Typical connection of a hard drive using SATA cables. The red cable is SATA data, and the connector on the right is the power SATA cable.


The different connection types we will cover here are: IDE (or PATA), SATA, PCIe, M.2, and power over SATA or Molex connectors.

IDE (Data connection)

IDE stands for Integrated Drive Electronics and is old technology for data cabling to hard disk drives, rarely seen nowadays and certainly no longer sold. However, here’s what it looks like for reference. It is also known as PATA (Parallel ATA).

Old IDE (or PATA) connections for passing data. These have been replaced with a SATA data connection, like the one shown  in the image below.

SATA (Data connection)

Current technology uses a SATA (Serial ATA) interface to transfer data. The connector for this cable is much more compact compared to the old PATA technology, and you will see these on most HDDs and SSDs today:

SATA Data cable

PCIeSSDs (Data connection)

A less known product is a PCIeSSD. This is essentially a SSD connected via a PCI express port rather than a SATA cable, but they can look quite different to a regular SSD. The advantage is fast access to storage as a PCIe port can transfer data at much higher speeds. Newer PCIeSSDs are known as ‘M.2’ SSDs and can reach some extreme read/write speeds.

One example of the latest M.2 SSD is the Samsung 950 SSD:

Samsung 950 M.2 internal SSD connects to the PCIe port on your motherboard and offers faster performance over a SATA connected SSD.

And here’s an example of a PCIeSSD prior to the M.2 generation:

Kingston’s Digital HyperX Predator is a PCIe Gen2 SSD.

SATA Power (Power connection)

In addition to data cabling, you’ll need to connect power to your drive. Most HDDs and SSDs use a SATA power cable from your computer’s power supply unit. It looks like the below:

SATA Power cable for hard drive


Molex Power (Power connection)

Alternatively, if you have an older power supply unit, you may have different plugs available to connect your drives and other hardware. The alternative to SATA power connectors is a Molex connector. Most HDDs will have the option for both Molex or SATA power connections, and you can use one or the other as you like.  However, most SSDs don’t have the option to accept Molex power plugs.


These are the two options for connecting power to your hard drive. You only need to connect one or the other. The top plug is a “Molex” connector, and the bottom plug is SATA power.




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