It's not just hard drive problem. If you buy a new storage rack at your home, it will be full in no time. No matter how many racks you buy, you will always find things fill those racks. This is like rain water filling up the lakes. if there is a lake, it gets filled. Or maybe it is called a lake because it gets filled. So, one can say that the disks create or cause the data. If there is no disk, there is no data.