(Im)proper way to do hacked DOS Version Multiboot

[a***@gmail.com]

First: What would I like to achieve:

Dos622 / Win98 / FreeDOS / potentially more Versions on same partition, properly working Multiboot without quirky jo.sys hacks.

What I have so far:

Standard Win98 installation with bootmenu (different configs)

FreeDOS on top of that

Boot process /files of those two doesn't interfere:

I created a secondary bootloader for freedos via FreeDOS sys:

sys a: c:\fdboot.bss /update

fdboot.bss is then chainloaded via grub2 (there is a linux installed on the same machine ofc)

FreeDOS then uses fdconfig.sys and in that i can configue a different command.com / fdauto.bat.

So far so good.

Now I want the same for Dos6.22

I could probably just rename IO.SYS to DOSKERN.SYS, put it on a: and then

sys a: c:\fdboot.bss /update /k doskern.sys

But then there still is msdos.sys which I also have to rename but still make the whole boot process work

For that I probably need to hack io.sys/doskern.sys and maybe msdos.sys

according to "the internet" in 6.22 io.sys loads the DOS kernel and calls its initialization routine. The kernel is stored in MSDOS.SYS. It then processes the CONFIG.SYS file.

I found CONFIG.SYS references in IO.SYS. Probably one one them is not just a text but the actual filename the kernel is looking for later on. But I found no reference to MSDOS.SYS.

So the question is: How is IO.SYS looking for MSDOS.SYS and how do I:

Either bake MSDOS.SYS and IO.SYS into one single file that I then could chainload just like FreeDOS kernel.sys

Alternatively hack IO.SYS so that it loads XYZ.SYS instead of MSDOS.SYS

[a***@gmail.com]

Or I could probably use a combination of FreeDos sys switches, but I don't understand how this is working exactly:

/OEM:MS /L 0x?? /K ??

[T. Ment]

Post by a***@gmail.com
Dos622 / Win98 / FreeDOS / potentially more Versions on same partition
properly working Multiboot without quirky jo.sys hacks.

I have two partitions: C FAT, D FAT32. Install DOS 6.22 on C, then Win98
on D: Edit msdos.sys to say

Bootmenu=1

Win98 can see both partitions, DOS 6.22 only C. Win98 boot loader takes
care of jo.sys automatically. Not hacky for me. If Win 3.1 is on the DOS
partition, remove it before installing Win98.

They say FreeDOS won't run Win 3.1, so I don't use it.