The capacity of a drive after it is formatted for a particular type of computer or computer system. Most hard disks have their capacities rated in absolute terms. In other words, they are rated at the total raw amount of storage space available. However, when a drive is formatted, various types of data are stored on the drive that are required by the formatting device to be able to read and write data to it. Not only does this data take up some space, but space is also lost due to how blocks of available space are allocated, which is different for each type of system. The amount of available space that shows up after being formatted on a specific type of system is the formatted capacity.