What is the empty space inside the character 'O' called?

What type of file does a cookie place on web site visitors' computers so that web site managers can customize their sites to their visitors' preferences?

Farah works in an office with two other employees. all three share a printer and an internet connection. the utility that makes this possible is defragger quicktime soho winzip

Assume that there is a 4% rate of disk drive failure in a year. a. if all your computer data is stored on a hard disk drive with a copy stored on a second hard disk drive, what is the probability that during a year, you can avoid catastrophe with at least one working drive? b. if copies of all your computer data are stored on three independent hard disk drives, what is the probability that during a year, you can avoid catastrophe with at least one working drive?