DOS is an old kind of computer operating system: the software that starts with the machine and makes the keyboard, screen, disks, and other programs work together. The letters stand for Disk Operating System — “disk” because it ran from, and looked after, the computer’s disks.

DOS is an old kind of computer operating systemDOS 是一種老式的電腦作業系統 the software that starts with the machine and makes the keyboard, screen, disks, and other programs work together就是開機時啟動、讓鍵盤、螢幕、磁碟和其他程式能一起運作的軟體 The letters stand for Disk Operating System這幾個字母代表 Disk Operating System（磁碟作業系統） "disk" because it ran from, and looked after, the computer's disks叫「disk」是因為它從磁碟啟動，也負責管理電腦的磁碟

In the 1980s and 1990s many home and school PCs used DOS (MS-DOS was the famous one). You typed commands in plain text, line by line; there were no big picture buttons yet.

In the 1980s and 1990s many home and school PCs used DOS一九八零、九零年代很多家用和學校的電腦都用 DOS (MS-DOS was the famous one)（最有名的就是 MS-DOS） You typed commands in plain text, line by line你要一行一行打純文字指令 there were no big picture buttons yet那時候還沒有大大的圖形按鈕

People still say “a DOS prompt” or “a DOS program” when they talk about that time. On a new laptop you do not install DOS as your main system; it is mostly computer-history talk now, unless someone is running very old software.

People still say "a DOS prompt" or "a DOS program" when they talk about that time講到那個年代時人們還是會說『a DOS prompt』或『a DOS program』 On a new laptop you do not install DOS as your main system新筆電你不會把 DOS 裝成主系統 it is mostly computer-history talk now它現在大多只是電腦歷史話題 unless someone is running very old software除非有人要跑非常老的軟體