一位： 计算机中的0或者1 bit
    常用的文件单位：字节 Byte
    1Byte = 8 bit

    100 Mbps / 8

    10MB/s

    1,000,000,000 Byte
    1 kB = 1024 Byte
    1 MB = 1024 Kb
    1 GB = 1024 MB
    1 TB = 1024 GB
    1 PB = 1024 TB
    1 EB = 1024 PB
    1 ZB = 1024 EB