A:Answer I read the answer someone gave about an indexing table and chuckled as that is the wrong answer. The reason the drive doesn't show as 4TB in your OS is because, since the beginning of time, hard drive manufactures consider 1 kilobyte as 1,000 bytes, 1 megabyte as 1,000 kilobytes, 1 gigabyte as 1,000 megabytes and 1 terabyte are 1,000 gigabytes. That is a marketing gimmick. In reality 1 terabyte is 1,024 gigabytes and so on down the line. That means manufactures consider 1 terabyte as 1,000,000,000,000 bytes, but in reality 1 terabyte is 1,099,511,627,776 bytes, because computers are binary systems (powers of 2). So a 4 TB labeled drive isn't actually 4 TB, it's actually a bit less, because manufactures are using the wrong value to represent gigabytes, terabytes, etc. as a marketing gimmick.
