When you purchase a pen drive or an SD card and cross check its storage capacity, you will find it has slightly less space than the manufacturer has promised to give. For example, a 32GB pen drive will give you only 29.8GB of storage capacity. Where has the rest 1.2GB gone? This is something we always have thought. And probably have heard the rest space is acquired by some sort of software which helps the storage device in working. But the fact is different. Generally 1 GB= 1024 MegaBytes. But in the storage device, the manufacturer keep 1 GB = 1000 MegaBytes. This is because designing the layout of a storage device with 1024 MegaBytes is quite complex. So for making design easier, they consider 1000 MegaBytes as one GB. In terminology, 1000 MegaBytes = 1 Gibibyte (GiB). This is why your pen drive or other storage device has slightly less storage capacity than it should be.