Re: emm386 hangs when booting from linux

From: Richard B. Johnson (root@chaos.analogic.com)
Date: Fri Feb 28 2003 - 17:54:45 EST


On Fri, 28 Feb 2003, H.Rosmanith (Kernel Mailing List) wrote:

>
> hello,
>
> for some reason, I am using the "switch to 16 bit realmode" function
> present in the linux kernel to execute various 16bit code. One thing
> that I am doing is to read the mbr off a harddisk to 0x7c00 and then
> jump to there. This allows to e.g. "quickboot dos" from linux without
> having to go through bios startup.
>
> I got this working with *one* exception: as soon as I load emm386
> in config.sys, the system hangs. It doesn't hang completely, e.g.
> the num-lock led changes light when pressing num-lock, and ctrlaltdel
> reboots the system. When I "REM"ark the emm386.exe, then dos will
> boot and display a "C:\>" prompt.

So you are trying a "home-brew" DOS-EMU which already exists and works
well.
emm386.exe attempts to go to protected mode. That's how it works.
That's how it's able to make "high-RAM" appear in "low-RAM" windows
for the emm386 specification. Of course it will fail when you
are in virtual 386 mode. The real DOS-EMU emulates the extended/expanded
memory specification so you don't need this in 'config.sys'. I sometimes
boot real DOS usinf DOS-EMU and it works fine. You need to configure
it so it will look at, say config.emu, instead of the DOS config.sys.
That way, you can keep boot-specific configuration files.

Cheers,
Dick Johnson
Penguin : Linux version 2.4.18 on an i686 machine (797.90 BogoMips).
Why is the government concerned about the lunatic fringe? Think about it.

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