A program, generally loaded manually on startup, which remains in memory to offer particular functions such as linking to a network or protection against the viruses. In Windows 95/98 TSRs currently operating are usually represented by icons in the System tray, such as the small loudspeaker which represents the volume control for the soundcard. A few of the TSRs are necessary, but many are installed manually by a specific function just to improve its own presentation, with no notion for anything else you may be doing, and may actually have a negative impact on everything else. Generally launched from the Startup folder in the Windows Start Menu.