Which file keeps command to execute automatically when operating system is started?

Question

Accepted Answer

The correct option is (3):
The correct file is Autoexec.bat, which stands for "automatically executing batch file." This file was a critical component in the startup sequence for MS-DOS and early Windows operating systems. Immediately after the system loaded the command interpreter (COMMAND.COM), it would automatically search for and execute the sequential list of commands contained within the Autoexec.bat file. This was the designated mechanism for performing all necessary startup actions, such as setting system-wide environment variables (like the PATH), configuring the system date and time, and launching any Terminate and Stay Resident (TSR) programs or applications the user wished to run immediately upon boot-up. Its function perfectly matches the requirement of keeping commands to execute automatically when the operating system is started.

The incorrect option is (1):
Config.sys is a system configuration file, and its purpose is fundamentally distinct from the Autoexec.bat file. This file is processed by the operating system kernel very early in the boot sequence, *before* the command interpreter even runs. Its primary role is to configure system hardware, load device drivers (using commands like DEVICE= or DEVICEHIGH=), and set crucial system parameters (like FILES= or BUFFERS=). It handles the initial hardware and memory configuration, but it is not used to hold general executable commands for automatic launch.

The incorrect option is (2):
Command.com is not a file that keeps commands to execute automatically; rather, it *is* the command interpreter itself. It is the primary executable file that acts as the user interface or shell for the operating system, receiving and executing commands. It is the program responsible for reading and interpreting the commands *inside* the Autoexec.bat file. Therefore, Command.com is the executor, while Autoexec.bat is the file containing the list of commands to be executed automatically.

The incorrect option is (4):
The option "All options are wrong" is incorrect because Option 3, Autoexec.bat, is the definitive and historically correct answer to the question. The Autoexec.bat file was designed explicitly to automate the execution of user-defined commands and programs as a final step in the MS-DOS boot process.