<Tr> <Td> 100 GB </Td> <Td> 100,000,000,000 </Td> <Td> 107,374,182,400 </Td> <Td> 7.37% </Td> <Td> 93.1 GB </Td> <Td> 100 GB </Td> </Tr> <Tr> <Td> 1 TB </Td> <Td> 1,000,000,000,000 </Td> <Td> 1,099,511,627,776 </Td> <Td> 9.95% </Td> <Td> 931 GB </Td> <Td> 1,000 GB, 1,000,000 MB </Td> </Tr> <P> The total capacity of HDDs is given by manufacturers using SI decimal prefixes such as gigabytes (1 GB = 1,000,000,000 bytes) and terabytes (1 TB = 1,000,000,000,000 bytes). This practice dates back to the early days of computing; by the 1970s, "million", "mega" and "M" were consistently used in the decimal sense for drive capacity . However, capacities of memory are quoted using a binary interpretation of the prefixes, i.e. using powers of 1024 instead of 1000 . </P> <P> Software reports hard disk drive or memory capacity in different forms using either decimal or binary prefixes . The Microsoft Windows family of operating systems uses the binary convention when reporting storage capacity, so an HDD offered by its manufacturer as a 1 TB drive is reported by these operating systems as a 931 GB HDD . Mac OS X 10.6 ("Snow Leopard") uses decimal convention when reporting HDD capacity . The default behavior of the df command - line utility on Linux is to report the HDD capacity as a number of 1024 - byte units . </P>

The amount of storage available on a hard disk drive is measured in