• The DOS control can be illustrated using the steps below:
• The boot loader loads the boot record to memory first, and then gives the control (boot programme) to the boot record.
• This programme now looks for the first entries IO.SYS and MSDOS.SYS.
• Now that the programme has control, it loads the IO.SYS file, which simply loads the MSDOS.SYS file and begins looking for the CONFIG.SYS file.
• Finally, control is given to the MSDOS.SYS file, which now initialises interrupt vectors and loads the COMMAND.COM file. Finally, the autoexec.bat file is loaded and run.

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