Boot Sectors!

As you know, computers needs to be booted up using a BOOTABLE DISK. A typical computer disk is divided into portions known as tracks and sectors. It so happens that when the computer starts up, it reads the first sector of the disk into memory, and executes it. This first sector is known as a boot-sector. A boot-sector can be written in assembly language. Here is how:
.model tiny .code entry: ; we enter the program jmp start ; required jump statement nop ; nop required to follow the jmp start: ;Add anything--put your code here org 510 dw 0aa55h ; ; add signature of BOOT SECTOR end entry	If you compile this in MASM, you'd get a 512 bytes long file. You can write this file to the first sector of the disk using some utilities like John Fine's Partcopy. Then you can boot the computer using the disk Remember, this is a Rough Guide!
You can easily add the 'Hello World' program given before to this boot-sector. You'd now have a boot-disk that says 'hello world' when it starts up! You might need more info to do other neat little things. For more on what the memory looks like, click here

Examples of other boot sectors:

MS-DOS 6.2 Boot Sector

The Boot Sector of the Windows 95 operating system

Disassembly of OS/2 boot sector

Boot Sector of Linux 2.0

Boot-Sector of an Individual operating system

I found the stuff above while surfing through the web. Though everything looks real, I have tested only the last example--and found it works.