A storage device is a piece of electronic hardware made to store data. Some storage devices have storage as their only function, while others are actually all-in-one devices, which can store data as well as perform other functions. Storage devices are divided into primary storage devices and secondary storage devices, but there are two different ways of considering which devices are primary and which are secondary. In one view, while current data is stored on primary storage devices, data that is not currently being accessed is stored on secondary storage devices, with all these devices on the computer. In the second view, all storage devices that are part of the computer are primary storage devices, while any storage that is peripheral is known as secondary storage devices.
USB flash drive, a type of secondary storage device.
According to the first view, the primary storage device is the computer’s random access memory (RAM). RAM contains the data immediately available to the CPU (Central Processing Unit) to which it is directly connected. Data in RAM is loaded by the operating system and active programs and requires electrical current to be maintained there.
Adding RAM – or random access memory – to your computer can increase its performance.
The computer’s hard drive, on the other hand, is secondary storage in this view because it is not directly connected to the CPU. As the data is stored magnetically, the data on the hard drive will persist after the computer is turned off, while the data in RAM will be lost when the computer is turned off as electrical current is no longer available.
Floppy disks are secondary storage devices.
In the second view, where primary storage devices include all of the computer’s original data storage – RAM and hard drives – secondary storage devices can be a number of other types of external storage and media. This type of secondary storage device can include additional internal drives, external hard drives, floppy disks, tape storage, and thumb drives. As far as optical drives are concerned, secondary storage devices can include CDs and DVDs as well as other optical media. Since the computer’s internal hard drive can be considered either a primary storage device or a secondary storage device, depending on which view is taken, it is important to be clear when discussing primary and secondary storage devices so as not to be misunderstood.
CDs are a secondary storage device.