Why do iPartition and display different sizes for the same partition?
Normally because the two programs are actually displaying the sizes of different things, or because they are using different units. iPartition generally displays the unformatted capacity of a partition, which is the total size of the disk sectors occupied by a partition. Some other disk utility software (including Disk Utility when you select a mounted volume) displays the formatted capacity of a volume, which takes account of the sizes of filesystem structures, and so will tend to be smaller than the size displayed by iPartition. It is also worth pointing-out that the unformatted capacity of a single partition that fills a disk is probably not the same as the quoted unformatted capacity of the disk, because the latter will generally not include the size of the partition map. This makes sense when you think about it… after all, the manufacturers of most disks don’t know which operating system you are going to use their disk with, and different systems use different amounts of space for
