TERMINATE-AND-STAY-RESIDENT TSR IS A SOFTWARE PROGRAM THAT REMAINS IN MEMORY UNTIL IT IS NEEDED, AND THEN PERFORMS SOME FUNCTION. AN GOOD EXAMPLE OF A TSR IS A VIRUS SCANNER, WHICH MUST REMAIN LOADED IN MEMORY TO HELP PROTECT YOUR COMPUTER FROM COMPUTER VIRUSES.

TSR THE TYPICAL METHOD OF UTILIZING AN INTERRUPT VECTOR INVOLVES READING ITS PRESENT VALUE (THE ADDRESS), STORING IT WITHIN THE MEMORY SPACE OF THE TSR, AND INSTALLING A POINTER TO ITS OWN CODE. THE STORED ADDRESS IS CALLED BEFORE OR AFTER THE TSR HAS RECEIVED THE INTERRUPT AND HAS FINISHED ITS PROCESSING.

TSR( TERMINATE BUT STAY RESIDENT) TSR PROGRAM IS DIVIDED INTO THREE MAIN PARTS EXAMPLE : REAL TIME CLOCK, SCREENSAVER DATA AREA RESIDENT ROUTINE INITIALIZATION ROUTINE