Capterra Glossary
A terminate and stay resident (TSR) is a software program that resides in a computer’s memory until it is called upon to execute.TSR programs were initially developed for single-tasking disk operating systems (DOSs). Computers that run under a DOS are only able to execute one program at a time, but with the help of TSRs they can allow programs to switch between tasks without having to reload the entire program. When a TSR is installed on a computer, a control character, otherwise referred to as a hotkey, is assigned to it. Once a computer user opens a software program, they can press the hotkey to immediately execute the TSR program. Examples of TSR programs include spell checkers, calendars, notepads, and antivirus software. However, today, DOSs are not commonly used in the business world. Most corporations use multitasking operating systems that are capable of task switching without the help of TSRs.
Since most small and midsize businesses use multitasking operating systems, such as modern Windows and Mac operating systems, they have little need for terminate and stay resident programs (TSRs). TSRs mainly function to assist single-operating systems with multitasking, which most modern operating systems are already capable of switching program tasks on their own accord. However, say a small tech startup obtains the copyrights for an old disk operating system (DOS) software, such as a legacy computer game. If they intended to alter its functionality, they would need to access the game using a DOS and run TSR programs to multitask during the software development process.