On the capacity of the memory card

Operating system volumes are calculated on a per 1024 as a binary, and memory card manufacturers in terms of computing capacity is per 1000-number system, both in binary differences caused a memory card capacity on "shrink". 4GB memory card, for example:vendor capacity calculation method: 4GB=4,000MB=4,000,000KB=4,000,000,000 byteconverted into operating system calculation method: 4,000,000,000 bytes/1024=3,906,250KB/1024=3,814.697265625MB=3.8GBWhile in the operating system, memory card formatted so that the system would take up some space on the memory card, available to system files using, so the operating system displayed in the memory card capacity and the nominal capacity will vary.