A 160GB drive has 160,000,000,000 bytes of data, which is really only 149 GB. (149 x 1024 x 1024 x 1024 = 159,987,520,000) It's a very questionable practice by drive makers to mis-label the drives. I have a 60GB drive that really has 57GB, I also have a 30GB drive that really has 28GB. My first IDE HDD was a 84MB Conner that only had 80MB 1 Gigabyte of data is 1,073,741,800 bytes, not 1,000,000,000 bytes, as drive manufacturers seem to think.