Hello,
I got this small example of a hello world OS from the web. It has 3 files: boot.asm, stripexe.cpp and copyboot.cpp. It gives the following instructions to make a bootable floppy:

1. Compile and link the file copyboot.cpp to copyboot.exe
2. Compile and link the file stripexe.cpp to stripexe.exe
3. Assemble BOOT.ASM using TASM
tasm boot.asm
4. Link the object file thus generated boot.obj
tlink /x /3 boot.obj
5. Strip the header off the file boot.exe
stripexe boot.exe boot.bin hdr.bin
6. Copy the boot sector code into a floppy
copyboot boot.bin
7. Restart The Computer

This all seems fine, and since now if I use FASM I think I can manage without the stripexe.cpp file since fasm can generate a flat binary file directly. But in the files provided i don't understand one thing in the stripexe.cpp code. The code opens the hdr.bin file and copies the 1st 512 bytes from the boot.exe file to it. Then it proceeds to copy the remaining bytes of boot.exe to boot.bin.
I don't understand this. My question is, does TASM generate a header which is 512 bytes in length??? I have also attached the file if someone is interested in going thru its code.
Any clarifications would be really helpful. Thank You.

Boot sector is 512 bytes?

yes the boot sector is 512 bytes but the thing is 512 bytes are written to hdr.bin while the file actually written to the boot sector is boot.bin

Tasm will generate whatever header you tell it too, and in your case that seems to be a standard DOS MZ executable. A much better thing to do would've been to simply make tasm spit out a .com file which could be written directly to the boot-disk instead of going through the trouble of generating a header only to remove it in the next step. I would probably just ignore all that and rewrite boot.asm directly for fasm, which won't be too hard. Just make sure you're not specifying any destination file format and that you include 'org 7C00h' to make sure your absolute addresses are calculated properly.

Thank you Ralph, well I was thinking of doing the same thing. I just need one help, how do I write my binary file to the 1st sector of the disk??

There's already a fasm source for writing a bootsector in menuetOS site to allow booting Menuetos from HDD

http://bitdog.home.att.net/temp/bootread.zip
with fasm source
bootread.com & bootwrite.com
for floppy drive A:

FreeBee rough draft version, but it works.