Quad Core          The CPU has four processors on the same silicon chip. See Dual Core.

QuickTime          Name of a video or animation format developed by Apple Computers.

Query              A set of data and conditions applied to a set of records to
                   retreive the required information. May apply to databases or
                   a plain file search.

Queue              A technique to store a series of data items or requests to be
                   dealt with in order. Types include FIFO (First In First Out) or
                   FILO (First In Last Out).

Quota              Usually applied to disks, to limit the amount of disk space can be
                   used. Applies to Windows NT4, 2000/3, XP etc.