A storage device is the physical hardware used to store data.In most cases, any type of file can be added to the storage device.Some storage devices are generic and can be used with a variety of hardware.When purchasing a storage device for a certain hardware, such as a computer or mobile phone, it is important to know what device is most suitable and compatible.While they are often associated with computers, hard drives can be found on other home electronics such as DVR or camcorder.Inside the hard drive is a physical disc that is constantly spinning (called a platter ).The speed of rotation of the disk is called RPM or number of revolutions per minute.The performance of the hard disk will be different, most of which are based on the speed of the rated speed of the hard disk.The USB flash drive is small (about the size of a pack of gum) and is most commonly used for portable storage devices that transfer files from one computer to another.No installation is required, and no additional software is required to transfer files to or from a USB flash drive.USB flash drives are protected by the enclosure, which makes them more reliable when in transit.The memory card is the smallest of the storage devices.They are portable and are most commonly used to increase the storage capacity of another device, such as an MP3 player or mobile phone.Memory cards have different interfaces (such as SD or MMC) that must be compatible with the device you intend to use.Unlike a USB flash drive, the memory card usually has little protection and is more prone to damage.