UNDERSTANDING HARD DISK DRIVE CAPACITY

Storage drive manufacturers measure storage drive capacity using the decimal system (base 10). Thus, for example, 1 gigabyte (GB) is calculated as exactly 1,000,000,000 bytes. Likewise, the capacity of a Fujitsu-branded Hard Disk Drive ("HDD") is measured using the decimal system. We explain this on our product packaging and on our website through the statement "One Gigabyte (GB) = 1 billion bytes."

Operating systems, including the operating systems on notebook computers, desktop computers or other electronic devices, use the binary system (base 2) of measurement. In binary, 1 GB is calculated as 1,073,741,824 bytes. This difference in how the decimal and binary numeral systems measure a GB is what causes, for example, a 120 GB Hard Disk Drive to appear as approximately 112 GB when reported by an operating system, even though the storage drive still has 120 billion bytes. You will see this difference if you look at how your computer summarizes the capacity of the computer’s HDD. The important point to understand is that the available storage capacity is the same no matter which system of measurement is used. No capacity is missing.

The storage drive in your Fujitsu-branded HDD, like all storage drives, uses some capacity for formatting, so actual capacity available for applications will be less. In addition, other factors, such as pre-installed systems or other software and media will also use part of the available storage capacity on the HDD.