noun
terminate-and-stay-resident program; TSR program
Computing term for a program that remains in memory after execution, common in older PC environments.
MS-DOS時代には、常駐型プログラムを使ってキーボードの機能を拡張していた。
In the MS-DOS era, people used TSR programs to extend keyboard functionality.
Compound of 常駐 (じょうちゅう, 'resident') + 型 (がた, 'type') + プログラム ('program'), a direct translation of the English computing term 'terminate and stay resident'.