1024字节=1kb1024kb=1兆1024兆=1G3G=1024b*1024Kb*1024Mb*3=3221225472b =3145728kb =3072Mb
3G=1024 X 1024 X 1024 X 3 =3221225472
320864256字节
3G*1024Mb/G*1024Kb/M*1024b/Kb