terminate and stay resident (TSR)

Terminate and Stay Resident (TSR) means as much as: "Terminate and stay in memory ". Terminate and Stay Resident are programs, parts of which are resident in the working memory even after termination. Only when the computer is switched off, TSR programs are deleted from the working memory.

The memory resident TSR programs, which can be stored in the Upper Memory Block( UMB), can be accessed by hotkeys, key combinations or the timer. A TSR program can be activated even if another program is running. Typical TSR programs are the mouse driver, calendar, calculators and the caches working in the background or the snapshot for the screenshot.

TSR programs can be called via interrupts in single-tasking operating systems while other programs are running. TSR programs were used in the Disc Operating System( DOS), but are not required in modern operating systems.