Storage device

Updated: 09/12/2023 by Computer Hope
Drobo storage device.

Alternatively called digital storage, storage, storage media, or storage medium, a storage device is any hardware capable of holding information either temporarily or permanently. The picture shows an example of a Drobo, an external secondary mass storage device.

There are two types of storage devices used with computers: a primary storage device, such as RAM (random-access memory), and a secondary storage device, such as a hard drive. Secondary storage can be removable, internal, or external.

Examples of computer storage

Today, three types of media store computer data: magnetic storage, optical storage, and solid-state storage. Below is a full list of all computer storage used over the evolution of the computer.

Hard drive

Magnetic storage devices

Today, magnetic storage is one of the most common types of storage used with computers. This technology is found mostly on extremely large HDDs or hybrid hard drives.

Compact Disc or CD

Optical storage devices

Another common type of storage is optical storage, which uses lasers and lights as its method of reading and writing data.

Solid-state storage devices

128 GB SanDisk Ultra Flair USB Flash Drive

Solid-state storage (flash memory) has replaced most magnetic and optical media as it becomes cheaper because it's the more efficient and reliable solution.

Online and cloud

Storing data online and in cloud storage is becoming popular as people need to access their data from multiple devices.

Paper storage

Punch card

Early computers had no method of using any of the technologies above for storing information and had to rely on paper. Today, these forms of storage are rarely used or found. The picture shows a woman entering data to a punch card using a punch card machine.


A hard copy is considered a form of paper storage, although it cannot be easily used for input without the aid of OCR (optical character recognition).

Why is storage needed in a computer?

Without a storage device, a computer cannot save or remember any settings or information and would be considered a dumb terminal.

Although a computer can run with no storage device, it would only be able to view information, unless it was connected to another computer with storage capabilities. Even a task (e.g., browsing the Internet) requires storing information on your computer.

Why so many different storage devices?

As computers advance, the technologies that store data do too, with higher requirements for storage space. Because people need more and more space, want it faster, cheaper, and want to take it with them, new technologies must be invented. When new storage devices are designed, as people upgrade to those new devices, the older devices are no longer needed and stop being used.

For example, when punch cards were first used in early computers, the magnetic media used for floppy disks was not available. After floppy diskettes were released, they were replaced by CD-ROM (compact disc read-only memory) drives, which were replaced by DVD (digital versatile disc) drives, which were replaced by flash drives. The first hard disk drive from IBM cost $50,000, was only 5 MB, big, and cumbersome. Today, we have smartphones with hundreds of times the capacity at a smaller price that we can carry in our pocket.

Each advancement of storage devices allows a computer to store more data and save and access data faster.

What is a storage location?

When saving anything on a computer, it may ask for a storage location, the location information is saved. By default, most information is saved to your computer hard drive. To move the information to another computer, save it to a removable storage device, such as a USB flash drive.

Which storage devices are used today?

Most storage devices mentioned above are no longer used with today's computers. Most computers today primarily use an SSD to store information and can use USB flash drives and access cloud storage. Most desktop computers and some laptops include a disc drive that read and write CDs (compact disc) and DVDs.

What storage device has the largest capacity?

For most computers, the storage device capable of holding the most data is the hard drive. However, networked computers may also access storage with large tape drives, cloud computing, or NAS (network-attached storage) devices. Below lists storage devices from the smallest to the largest.


Many storage devices have been available in many different capacities. For example, over the evolution of the hard drive, their storage capacity has increased from 5 MB to several terabytes. Therefore, the list below only provides a general idea of the size difference between each storage device, from smallest to largest storage capacity. There are exceptions.

  1. Punch card
  2. Punch tape
  3. Cassette
  4. Floppy diskette
  5. ROM card / ROM cartridge
  6. Zip disk
  7. CD
  8. DVD
  9. Blu-ray disc
  10. Flash jump drive
  11. Hard drive / SSD (solid-state drive)
  12. Tape drive
  13. NAS / Cloud Storage

Are storage devices input and output devices?

Storage devices do not directly get input from the user and do not display output to the user. So, when thinking about an input device or output device in this way, a storage device is not an I/O device.

However, going deeper into the computer architecture, an I/O device is any device that gets input and output from the computer CPU (central processing unit) and memory. So, because many storage devices (e.g., hard drive) directly communicate with the CPU and memory, they are considered an I/O device.


We've found it's less confusing for users to refer to any device capable of storing and reading information as a "storage device," disk, disc, drive, or media and not an I/O device.

How do you access storage devices?

Accessing a storage device on your computer depends on the computer's operating system and how it's being used. For example, with Microsoft Windows, you can use a file manager to access the files on any storage device. Microsoft Windows uses Explorer as its default file manager. With Apple computers, Finder is considered the default file manager.

What is the latest storage device?

One of the most recent storage device technologies is NVMe, with SSDs and cloud storage. Also, older technologies, like hard disk drives and tape drives, are always developing new techniques to allow for more storage. For example, in August 2023, IBM announced a tape drive cartridge capable of holding 50 TB or 150 TB with compression.

CD terms, Cloud, Floppy drive terms, Hard drive terms, Hardware terms, I/O Device, IPOS, Memory terms, Non-volatile, Optane memory, Permanent storage, Remote storage, SAN, Tape terms