Mebibyte

A unit of electronic digital storage capacity similar to a megabyte equal to 2^20th (2 to the 20th power) bytes. It was created to reduce the confusion of inconsistent capacity reporting of devices like hard drives. The box of a hard drive might say 500MB (megabytes) while your operating system shows the capacity as something around 480MB. The difference is likely due to some space on the disk being used to store file system metadata, and your computer measuring in MiB (mebibytes). The meta data is used to keep track of where your files are, when they were modified, and an assortment of other important information your computer and its software needs to use them.