TSR

詳細解釋：

TSR

n.（名詞）
A program, such as a spell checker or calendar, that remains loaded in memory so that it may be quickly recalled while another program is running, as found in operating systems which do not allow multitasking.
常駐程式：一直存在於記憶體中的程式，如拼字檢查或月曆，在不允許處理多任務的作業系統中其它程式運行時其可被即刻恢復

來源：
t(erminate and) s(tay) r(esident)
t(erminate and) s(tay) r(esident)