China DOS Union

cstrt086.asm is my modification of the startup file of Open Watcom C/C++ 1.3, making the startup address of the program cstart become 0000:0000, which makes it easier to relocate the program. In this way, the executable image file can be generated by EXEFLAT.EXE (only for 16-bit DOS real mode);

sys_demo.bat is a batch file that turns demo.exe into KERNEL.SYS that can be booted from the hard disk by FreeDOS boot loader;

Set the starting address in Open Watcom C/C++ 1.3 link switches --> 3. Advanced switches to _cstart_, compile MAIN_boot.c and cstrt086.asm, name the executable file demo.exe, double-click (execute) sys_demo.bat; you can get KERNEL.SYS;

Replace KERNEL.SYS with FreeDOS's KERNEL.SYS (you can rename FreeDOS's KERNEL.SYS) to realize the hard disk boot of FreeDOS boot loader;

Extract the files in rtCell_img.rar and Qemu.rar to the same folder (without any subdirectories), double-click (execute) rtCell.bat to see that KERNEL.SYS is loaded by FreeDOS boot loader and executed on the emulator;

*****************************************************
***This file is best executed with a virtual machine or emulator to avoid damaging hard disk data***
*****************************************************

If any friend has questions, new ideas, or finds errors, please contact: taowentao_twt@163.com

[ Last edited by taowentao on 2005-9-3 at 15:53 ]

"China DOS Union Forum » DOS Development Programming & Development Exchange (Development Room) ---> Real-time microkernel that can read and write FAT16 format files on the hard disk" There are also files related to reading and writing FAT16 format files on the hard disk that can be downloaded.

Among them, the C code for reading and writing the hard disk is only more than 400 lines;
The C code for reading and writing FAT16 format files is only more than 620 lines.

Very suitable for writing your own boot programs or for embedded systems.

I still can't understand these programs now, but I admire that you understand the operating system so thoroughly!

How to obtain the source code of FREEDOS32? The website says that it is necessary to use a certain synchronization download tool, but I have tried several times without success.

I tried, and I can download directly
"http://prdownloads.sourceforge.net/freedos-32/fd32-0.0.5-src.tar.bz2?use_mirror=umn"

I'm really dizzy. (Sweat...)
I only focused on the "Latest source code from CVS"...

Both rtCell_img.rar and Qemu.rar should be downloaded simultaneously and extracted into the same folder (without any subdirectories) to see the execution result on the emulator. To make your self-compiled program be booted by the bootloader and executed correctly, there should be no DOS calls in this program; it can only call BIOS functions or your self-compiled hardware driver programs. There are many resources available online for reference, please friends query them.

The rtCell.img in rtCell_img.rar is a hard disk image file. You can use winimage to add or delete files/folders in it (winimage can be downloaded from http://as.onlinedown.net/). So as to demonstrate the program you wrote that is started by the "bootloader" on the emulator.

Make the following modifications to the file:

public _arg1
public _arg2
.
.
.

_cstart_ proc near
jmp around
_arg1:
DB 'a', 'r', 'g', '1'
_arg2:
DB 'a', 'r', 'g', '2'

around: sti ; enable interrupts
mov dx,DGROUP

mov ds,dx
mov es,dx
call _CMain
_cstart_ endp


Then reference in the C program: extern DWORD arg1, arg2;

Modify the values of arg1 and arg2 in the executable file from the bootloader (dynamically) or using a binary modification tool (static), so that parameters can be passed to your program.

Off-the-BIOS FAT16 file operations, please go to

"DOS Development Programming & Development Exchange (Development Room) ------>
Read-write hard disk FAT16 format file real-time microkernel (including source code)"

to view the source code.

I will provide a file:
This is a protection module of a hard disk protection card, write hj.bin into the BIOS chip of the mainboard. Plug in the network card to replace the hard disk protection card. Hope you can write a program to load and run it under DOS, or make it into KERNEL.SYS like the program you posted on the DOS forum to start and test its performance!

[ Last edited by hnlyzhd on 2006-2-5 at 22:48 ]

Please provide the relevant Chinese content about "hj.bin 的调用接口作个详细说明，列出其初始化入口地址" so that I can translate it. Currently, the content you provided is incomplete for translation. Please supply the full relevant Chinese text.

Too profound!! Can't understand

The foundation is not enough~~~ Too advanced~~~