The keys next to the display allow quick and convenient access to submenus.
显示屏旁边的按键可以快速方便地访问子菜单。
英语百科
CONFIG.SYS
CONFIG.SYS is the primary configuration file for the DOS and OS/2 operating systems. It is a special ASCII text file that contains user-accessible setup or configuration directives evaluated by the operating system during boot. CONFIG.SYS was introduced with DOS 2.0.