fdisk  -l Partition table entries are not in disk order.Units: sectors of 1 * 512 = 512 bytesSector size (logical/physical): 512 bytes / 512 bytesI/O size (minimum/optimal): 512 bytes / 512 bytesDisklabel type: dosDisk identifier: 0xc3072e18Device     Boot    Start      End  Sectors  Size Id Type/dev/sdb1  *       16128 30489407 30473280 14.5G  c W95 FAT32 (LBA)/dev/sdb4       11580256 13523807  1943552  949M  0 Emptysdb1+sdb4=14.5g+949M=15.4gWhy is this : Disk /dev/sdb: 14.6, 15610576896 bytes, 30489408 sectors, in the fdisk -l info?It says that the whole sdb space is 14.6 GiB. Why is it not the 15.4 GiB?Why is there about 0.8 GiB space lost?
Why isn't the whole space equal to all the sub partitions?
partition
You disk size is 14.538 GiB (30489408 sectors * 512 bytes /1024/1024/1024).Its partition table is seriously broken as sdb4 is overlapping sdb1.You should remove sdb4 as soon as possible and in any case, you shouldn't use that fourth partition without a very strong risk of corrupting sdb1 content.