As the use of technology continues to grow at a rapid rate, the ability to store large amounts of information becomes increasingly important. This information must be easy to retrieve but difficult to erase or damage. Mass data storage is a term used to describe the many means in which large amounts of data can be stored in order to be used or protected. Types of mass data storage include hard disks, optical disks (CDs and DVDs), USB drives, and secure digital (SD) cards. Each type of storage method has benefits and drawbacks relating to its intended use.
Hard disk drives can be portable or permanent installations in a computer or other electronic device. They can hold large amounts of data, but can be expensive in relation to other devices with smaller capacities. A system of magnetic disks is used to store data, making it easy to retrieve and organize.
USB drives act much like portable hard drives in that they allow data to be transferred from one place to another. A small, rectangular device is plugged into a computer's USB port, enabling file transfer between the two devices. The most common name for a USB drive is a flash drive. These are extremely portable and relatively inexpensive compared to larger mass storage options, but they do not have the capacity to hold as much data.
Optical data disks make use of a special type of laser to create and read data. They can store significant amounts of data, but retrieval is slower than that of many other methods and specialist equipment is required. DVD disks have a larger capacity than CDs. Some types of disks are read only, meaning that data can only be written to them once, while those that allow data to be re-written are more expensive. Many optical disks can be used in other electronic equipment to access stored data, including music players and DVD players.
Secure digital (SD) cards and other digital cards are most often found in digital cameras, music players and cell phones. They are very small and hold relatively large amounts of data. They must be read by compatible readers and can only display data in an appropriate device. For example, a digital card holding music files cannot be read by a camera.
Mass data storage is not the same as computer memory. This is, in fact, a temporary type of storage on a computer that cannot be accessed once the computer is turned off, and cannot be transported between devices. The amount of data that can be stored on a mass data storage device is measured in bytes. Capacities range from the smallest amount, kilobytes (KB), to the largest amount, terabytes (TB). A kilobyte is 1,024 bytes, a megabyte (MB) is 1,024 KB, a gigabyte (GB) is 1,024 MB, and a terabyte is 1,024 GB.