GB
Gigabyte. WD defines a gigabyte as 1,000,000,000 (one billion) bytes or 1000 (one thousand) megabytes.
GMR
Giant magnetoresistive. An advanced form of head technology.
GPL
General Public License. Free software license which grants recipients rights to modify and redistribute the software which would otherwise be prohibited by copyright law.
GPS
Global positioning system. Provides specially coded satellite signals which can be processed in a GPS receiver to compute position, speed, and time.