I want to free up space on my hard disk drive but I can't seem to get an accurate account of its used capacity. The computer says I'm using 87.2 gigabytes of 97.72GB of available capacity on what is supposed to be a 100GB hard drive. I do plenty of video editing and my calculations show 81.42GB of capacity used. What's going on? Jennifer Deayton, Mid-Levels
DQ: A hard disk drive must first be formatted, or initialised, so a user can find and access data stored in the device. Depending on the computer hardware and its operating system, the hard disk drive is typically divided into discrete sectors. Each sector holds a specific amount of data, usually 512 bytes, but it can vary.