Like PC operating system, when we install Windows or Ubuntu OS into a PC, it will allocate some hardware disk space to store system files, and it is the same as android. when we flash android firmware into the box storage, it will occupy some 1G~2GB for those files(depending on how many apps and addons we put into the firmware).
android system still need to allocate some private space for private using, such as cache, store OTA package, otherwise, the android box system no space to hold a full OTA package.
it's about 512MB~ 1GB, depend on what size the firmware is.
so , the balance for end users to use is less than the total space of the storage installed in box.
1.There are other factors made usable storage less, the de facto standard for flash or emmc storage description is 1000B=1M, not like 1024B=1M in computer technology.that's a worldwide standard, especially in harddisk in PC.
2.Android need file system to hold files , so file system also need private space to hold file attributions ,index, for management.
In a word ,android itself only show the space that customers can use, not the total space on board.
