Computer storage is the process of storing digital information on electronic, optical or silicon-based devices. It is used in offices, data centers, edge environments and people’s homes, as well as mobile devices such as smartphones.

Depending on the type of storage, it can range from a few thousand kilobytes to tens of megabytes or even gigabytes. How much space a file needs depends on the application, how long it must be stored, applicable compliance regulations and other factors.

Hard disk drives (HDDs) and flash-based solid-state drives (SSDs) are among the most common types of computer storage media. These devices store data on concentric tracks made up of minuscule bumps that are detected by a laser contained within the drive. The way the laser reflects or bounces off these bumps determines whether they represent a 0 or 1 in binary, which is the language used to communicate digital information.

CDs, DVDs and Blu-ray discs are another common form of computer storage. Most desktop computers and some laptops have a disc drive that can read and write these disks.

Magnetic tape is also an auxiliary storage medium, often used for backup. It is less expensive than a magnetic disk but access times are much slower because it is sequential-access memory, which means data must be read and written in order.

Floppy disks are another type of auxiliary storage device, but they have been gradually becoming obsolete as hard-drive capacity has grown nearly 30 percent per year since the 1980s. The floppy disk has been a primary source of data on computers for several decades, but its storage capacity is now small enough to fit on USB flash drives or in cloud storage.

Tapes are also a popular secondary storage medium, though they are not as reliable or fast as a magnetic disk. Unlike disks, tapes are not indexed, which means the information on them must be retrieved in its original order.

Other auxiliary storage devices include flash memory cards, USB drives and external hard-drives. All of these have a limited amount of capacity and are not very flexible, but they do allow you to move data around your computer system without having to re-copy it.

These storage devices are also frequently referred to as secondary or tertiary storage. They are often used to store a wide variety of data that cannot be easily copied to other devices. They are generally considered to be non-volatile, which means they do not lose their ability to hold information when the power is turned off.

The smallest unit of storage is called a bit, which has a value of 0 or 1. Text, numbers, images and audio are all represented in this way.

A byte is the most common unit of storage, and it contains eight bits. There are many different byte sizes, but the most commonly used ones are kilobytes and megabytes.

Typically, computer and storage systems use two standards when measuring their data amounts: a base-10 decimal system and a base-2 binary system. For small data amounts, a discrepancy between the two makes no difference, but as storage capacity grows, a disparity can create inefficiency and make for a less responsive user experience.