Apple iphone6s 64GB Real space why only 55.6GB?

In the computer storage unit is the smallest B (byte), an English character needs to occupy 1 bytes of space, a Chinese character needs to occupy 2 bytes of space, the conversion between the units are as follows:

1kb=1024b
1mb=1024kb
1gb=1024mb= 1,073,741,824b
1tb=1024gb
---The following units are rarely used, which are rarely mentioned-------------
1pb=1024tb
1eb=1024pb
1zb=1024eb
1yb=1024zb

About the space capacity of the problem, in fact, manufacturers and we often say that the conversion method is different.

Theoretically 1GB=1024MB, but the manufacturer usually 1GB=1000MB (about equivalent), actually even smaller than this capacity, almost 900 m on the task is 1GB to calculate, this is why.

This is because the operating system of the computer or mobile phone device is based on the capacity of B for the unit conversion, but the computer profiteers sell capacity by B as a unit. B is 1000, and B is 1024, so the promotional time marked capacity 64G refers to 64Gb instead of 64GB, we may wish to convert the following:

64GB=64*1000*1000*1000/1024/1024/1024=59.6GB see no, the 64Gb version of the actual capacity after the conversion of only 59.6GB, less 5GB more capacity.

In addition, iOS itself occupies more than 3GB of fixed space, so iphone6s bare metal remaining 55.6GB space is not surprising, for the manufacturer by B instead of B to calculate, has been the industry's unspoken rules, but also well-known things, users as early as the hard disk era of a lot of spit.

About the iphone6s 64GB version of why the actual free space than the 64GB to be small, is the top 2 reasons, the biggest reason is that the manufacturer's standard and theoretical standard value is not the same, the other will occupy part of the space, so the actual available space, than the standard small 8.4GB, for users, Still not a small loss.