How to boot into dos
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If you are using DOS operating system, then the boot process starts by booting the equivalent of DOS. A specific operating system starts to load in sequence; this is known as booting DOS system. You can either boot through a hard disk or a floppy disk, the process will be slightly different. Since floppies are not partitioned, they have no master record of booting. So the boot records are skipped.
- Specialized software
The boot code is loaded by the BIOS which is present in the master boot record, the control of the system is then transferred to it. Then, the code to boot is executed.
Then the process of the master partition table is being examined by the master boot code. If an extended DOS partition is available, it has to be determined whether there is a mention of the bootable partition made on the partition table.
If an extended partition is on the disk, it loads, and the extended partition table sees if there is an extension to a different partition table. If it happens, then the second table is looked at to get information on the second logical volume. This is a continued process till all the extended partitions are loaded and given recognition by the system.
Once all the extended partition information is loaded, the boot code tries to start the boot partition which is marked as active, any error is removed. If the boot device is not located, then the error occurs, it will say no boot device. The boot code will boot a primary partition if a active mark is made.
The boot sector gets loaded into memory, and the boot code takes control of the boot process that is left.
The disk structure is examined by the boot code to make sure that all is right. If something is wrong, the rest of the booting process will end in an error.
The directory of the device is search by the boot code for getting the operating system.
An error message will show up if no operating system files can be found. It will say to replace and press any key when ready. It means the operating system could not be booted.
The operating system is loaded by the boot program into memory and controls it. Booting process is over now.