What is a computer data storage device?

A computer data storage device is intended to preserve data even when the machine is turned off. This could be a hard drive, an SSD or even a DVD. When we talk about data storage on a computer, we typically mean long-term or permanent storage. This is also known as non-volatile storage. 

However, computers also have temporary data storage devices in the form of computer memory (RAM). RAM can only operate while the computer is turned on, which is why it’s called volatile storage. 

The speed of data access is also a factor. Computers need to find their data quickly to operate efficiently. Long-term storage is often much slower than temporary computer storage, and different storage mediums also operate at different speeds. 

Let’s explore this in more detail. 

Non-volatile storage is storage that maintains the data even when there is no electricity powering the device. The best example is a hard disk drive (HDD) or solid state drive (SSD) that holds all the data saved to your computer, but there are a variety of ways you can preserve data when your computer is switched off. Find out more about the differences between a hard drive and an SSD.

Your internal hard drive or SSD like a NVMe drive is the most common example of a computer data storage device. Each of them is designed to preserve data without the need for power. These are common and reliable devices, but the data they hold can still be affected by power surges or magnetic fields, which is why learning to back up your device properly is important. 

External hard drives and USB flash drives are examples of external storage devices. Once the data is saved, the device can be disconnected from the computer and the data will be safe. These devices have the same benefits and risks as internal devices, and they’re an easy way to make additional backup copies of your data. 

You can also have network storage devices (NAS) operating on your network. These are networked computers which specialize in data storage rather than applications or processing power

Optical storage devices like CDs, DVDs and Blu-ray discs have been around for some time, and they have their own advantages and disadvantages as a computer storage medium. Optical discs are written and read by a laser, so they operate more slowly than HDDs or SSDs, and they run the risk of getting scratched which can affect data recovery. On the other hand, they can pack a huge amount of data into a small area (up to 128GB on a quadruple-layer Blu-ray disc). They also don’t require any power, and because they are based on optical technology rather than magnetic or electronic, they are immune to magnetic fields and power surges. 

The use of magnetic tape as a storage medium has been around longer than the microchip but is still a practical solution today for an efficient archive of valuable data. Cassettes containing tightly packed spooled tape are used to record data with very high densities for a relatively low cost per GB. Tape is a linear storage medium which makes it impractical for day-to-day use but perfect for backups. It’s also immune to power surges, though it can still be affected by electromagnetic interference. 

Cloud data storage involves using remote servers accessed via the internet to store your data. These exist in huge server farms, filled with thousands of servers designed to provide quick access and data redundancy. Services like Dropbox or Google Drive are examples of cloud storage.   

Learn more about the difference between memory and storage. 

The first classification of computer data storage is between volatile and non-volatile storage. An example of volatile storage is the computer’s working random access memory (RAM) that stores data only while the computer is switched on. RAM allows your computer to have multiple files and programs open with the ability to access any of them almost instantly. Working memory can be shared among the whole system, but different computer devices may have their own dedicated memory to support their specialized functions.  

For example, graphics cards often have their own dedicated, very fast RAM on board to support their processing. CPUs also have dedicated cache memory which is extremely fast RAM built into the CPU. This is the component that stores the immediate data being accessed by the CPU. Important instructions stored here can save processing time. CPU cache and video card memory are not user-serviceable, but you can upgrade your computer memory.  

It’s easy to upgrade most laptop and desktop computers if you need more storage or memory, and external drives can be connected to any device. If you feel like your computer storage is running out of space, or if you just need to make a safe backup of the data you have, you should consider an upgrade. The Crucial Upgrade Selector can help you find compatible parts if you know what system you have, and if you don’t, System Scanner can do the hard work for you.