China DOS Union

I made a DOS floppy disk by myself.
Below is my menu.lst
color white/green yellow/green
timeout 10
default 0

title 1. MS-DOS 7.10
root (fd0)
chainloader /io.sys

title 2. Boot from Hard Drive
root (hd0,0)
chainloader +1

title 3. Boot from CD Drive
cdrom --init
map --hook
root (cd0)
chainloader /io.sys

title 4. Reboot computer
reboot
The key is the option to boot from CD. The DOS boot CD is okay, but if it's a WinPE boot CD or an XP, VISTA installation CD, etc., which have no io.sys, it prompts that the file is not found??? Is there a universal CD boot method, how to modify it?
Another problem is that after booting from the floppy disk and before entering this menu, there are a lot of asm codes like int?? on the screen, which looks messy. Is there an option for silent boot, with no other information except the menu and error prompts?
Thank you!

You are using an old version. In the new version, there is no such int?? information by default. In addition, the new version has a debug off command that can turn off most non-severe problem reports.

The boot CD should probably be like this:
title 3. Boot from CD Drive
cdrom --init
map --hook
root (cd0)
chainloader (cd0)

This doesn't guarantee 100% success. There are two reasons:

1. When cdrom --init fails, your hardware is not supported by grub4dos. That goes without saying.
2. When chainloader (cd0) fails, it is generally caused by the boot mode of the CDROM. Only CDROM discs in no-emulation mode can be successfully booted via chainloader (cd0). Other modes are not supported currently, but will be supported in the future.

Of course, you can also search the Internet for other startup methods related to CDROM, which can be used in conjunction with the floppy disk emulation function of grub4dos. I won't go into details here.

Changed to a new version, and those information are gone, thank you

title 3. Boot from CD Drive
cdrom --init
map --hook
root (cd0)
chainloader (cd0)
I tried it, but it didn't work.
Finally, I found that just change it to this:

title 3. Boot from CD Drive
cdrom --init
map --hook
chainloader (cd0)
boot
Can boot smoothly, very strange, but tried various boot disks and installation disk isos, winpe, dos, etc. can all boot from the CD smoothly.
It seems that the key is the last line
boot