SoftICE under DOS16, anybody? __/__ Re: [Qemu-devel] [PATCH] intentinoal slowing down qemu - brake

[Martin Bochnig]

Johannes Schindelin wrote:

>>>This patch adds support for slowing down qemu and saving cpu load.
>>>      
>>>
>>if you're using the right kernel, QEMU will sleep while there is
>>nothing to be done.
>>    
>>
>
>As was stated by the OP, this is for DOS games. So, there is no "nothing 
>to be done". Further, you are assuming everybody uses Linux. What makes 
>you think so?
>
>Besides, your "nice" would not do the same thing, you know? You'd need 
>_another_ tast _using_ the CPU to slow down QEmu. Which would burn through 
>the battery like hell.
>
>Ciao,
>Dscho
>  
>

Might something like that help SoftICE for DOS16 to run properly without
freezing the whole guest after one or two ^D's  (i.e. for setting
breakpoints and switching back to the dos command.com)?
WinICE (on DOS386 a.k.a. {win386.exe / chicago's dos386.exe, now called
vmm32.vxd}) does/did already work well, when I last tested this a year
ago, but SoftICE for real mode DOS would always hang the whole guest
when being run inside QEMU (emulation case, not yet tested in case of
x86_x_x86 virtualization).
The same happens when using the Insignia_SoftWindows Pentium-ISA-PC
Emulator on Solaris_sparc, running any version of (MS-/IBM) or DRDOS.
Bochs claims to provide a more accurate emulation than qemu (at the cost
of making it marginally slower), but doesn't fix the SoftICE issue either.

It does - on the other hand - work as expected inside any version of
SunPCi, which only emulates a bit of io and graphics, but uses a
physical x86 cpu, rather than emulating it (I think it doesn't even have
to virtualize it, because nobody else is using the cpu sitting on that
pci card).

Has onybody found a way to work around the SoftICE_for_DOS16
instabilities under qemu?
(btw, my problems *are* qemu-dependant, not caused by an incompatible
himem.sys or anything of that sort / identical diskimages tested under
SunPCi, SoftWindows and qemu_for_SolarisSPARC-Hosts).

Thanks,
Maddin