GB - One gigabyte (GB) is equal to one billion bytes when referring to hard drive and SSD capacity. One terabyte (TB) equals 1,000GB, and one petabyte (PB) equals 1,000TB. Accessible capacity will vary depending on the operating environment and formatting. MTBF - MTBF target is based on a sample population and is estimated by statistical measurements and acceleration algorithms under nominal operating conditions. MTBF ratings are not intended to predict an individual drive’s reliability. MTBF does not constitute a warranty.