In the SD card, 1G=1024M, 1M=1024K.
1. The conversion method is different, only 1M in the hard disk is equal to 1000K.
2. For chip storage devices such as memory and flash memory, the capacity must be standard, and there will be no fluctuations. 128M of memory is 128M, and there is no other excess attenuation.
3. A small part of SD itself is used for other purposes, which cannot be used by users. For example, some space will be reserved, or index occupation, system file occupation, and so on.
The most common is the partition table occupation, which will exist as long as you format the SD card, and the space occupied is proportional to the number of files, as well as the occupation of the file system, but these are very small, this is a normal phenomenon, users do not need to worry .