Hello,

I have a memory trouble with an old DOS OS from Digital Research called Concurrent DOS.

It worked fine till Qemu v0.11.1.
I use Qemu to make a legacy application run without any modification.

Starting with Qemu 0.12, my legacy application has not enough memory to run.
Actually it seems that the SeaBIOS doesn't use the same memory mapping than PC-BIOS used to, causing trouble to my application.

Is there any way to get SeaBIOS use (more or less) the same memory amount and memory mapping than the older PC-BIOS ?

I tried to recomplie SeaBIOS 1.7.0 with less options but the result is the same.
Here is my .config file :

CONFIG_RELOCATE_INIT=y
CONFIG_ATA=y
CONFIG_FLOPPY=y
CONFIG_PS2PORT=y
CONFIG_SERIAL=y
CONFIG_LPT=y
CONFIG_DRIVES=y
CONFIG_OPTIONROMS=y
CONFIG_PMM=y
CONFIG_BOOT=y
CONFIG_KEYBOARD=y
CONFIG_KBD_CALL_INT15_4F=y
CONFIG_MOUSE=y
CONFIG_NO_VGABIOS=y
CONFIG_DEBUG_LEVEL=0

I also join two print screen of the same C-DOS utility. One with Qemu 1.0 and SeaBIOS 1.7.0 and the other with Qemu 0.10.0. The amount of memory is quite different between the versions.
If you want to try, get this floppy :
https://docs.google.com/open?id=0B7mz0vq6Rpb7Q0tYbmxMVzVqTms
and then type :
STOP

If you have any idea...

Alain