MSD is primarily related to storage devices that provide consistent and permanent storage capacity. MSD is connected to the computer/server via a data transfer interface, such as SCSI, USB or even Ethernet (for storage area networks). Some of the common MSDs include floppy disk drives, optical drives, hard disk drives, tape drives, external hard drives, RAID and USB storage devices. Currently, typical MSD devices provide anywhere from a few gigabytes to petabytes of data. Internal MSDs generally can't be removed, whereas external MSDs can be easily removed, ported and plugged into another computer.