DOS Startup Files: AUTOEXEC.BAT vs CONFIG.SYS Which statement correctly describes the role and timing of AUTOEXEC.BAT during a standard DOS boot sequence?

Introduction / Context:
A classic DOS boot sequence processes two well-known startup files: CONFIG.SYS and AUTOEXEC.BAT. Knowing the order and purpose of these files is fundamental for troubleshooting device-driver issues, memory management, and environment configuration on legacy systems.

Given Data / Assumptions:

• DOS loads system kernels first (IO.SYS and MSDOS.SYS) before user-editable startup files.
• CONFIG.SYS contains DEVICE and memory manager directives.
• COMMAND.COM loads and then runs AUTOEXEC.BAT to set user environment and TSRs.

Concept / Approach:
CONFIG.SYS is processed first to load low-level drivers (for example, HIMEM.SYS, EMM386.EXE) and to set system limits. Afterward, the shell (COMMAND.COM) starts and executes AUTOEXEC.BAT. This second file typically sets PROMPT, PATH, and launches terminate-and-stay-resident utilities (mouse, keyboard, network logins, etc.).

Step-by-Step Solution:
System powers on → BIOS POST completes.Boot sector loads IO.SYS and MSDOS.SYS.DOS reads CONFIG.SYS and loads device drivers and managers.DOS loads COMMAND.COM (command interpreter).COMMAND.COM then executes AUTOEXEC.BAT to finalize the user environment.

Verification / Alternative check:
Temporarily rename AUTOEXEC.BAT and reboot; devices from CONFIG.SYS still initialize, but environment variables and TSRs do not load, demonstrating that AUTOEXEC.BAT runs after CONFIG.SYS.

Why Other Options Are Wrong:
Option B: AUTOEXEC.BAT does not contain Windows configuration files; those are managed separately (e.g., WIN.INI, SYSTEM.INI in Windows versions).Option C: AUTOEXEC.BAT is not the same as CONFIG.SYS; they have different purposes and formats.Option D: There is no concept of “system polarity” in DOS startup files.

Common Pitfalls:

• Loading TSRs in CONFIG.SYS rather than AUTOEXEC.BAT.
• Expecting PATH or PROMPT to be active before COMMAND.COM executes AUTOEXEC.BAT.
• Confusing Windows startup with DOS startup processes.

Final Answer:
Is run after config.sys on system boot-up