🚀 go-pugleaf

In article <1991May10.204939.17701@herald.usask.ca> lowey@herald.usask.ca (Kevin Lowey) writes:
>From article <1991May9.182102.29631@netcom.COM>, by resnicks@netcom.COM (Steve Resnick):
>
>> The DOS box runs in real mode which means there is not protection. If you
>> crash the DOS box, it could very likely kill the rest of the machine. 
>> OS/2 2.0 shouldn't have this problem.
>
>I've been running OS/2 from 1.0.  I've crashed the DOS box many times.  
>Most of those times, all I have to do is press <ATL>-<ESC> and I am back in my
>OS/2 sessions.  They still operated fine.
>
>The only exception to this is if the DOS program screws up the keyboard 
>interrupt so that the <ALT>-<ESC> doesn't get passed through to OS/2.
>

I have managed to get things like: An internal processing error was encountered

which dumps things like registers and such and then says The system is stopped.

If you really want to make OS/2 crash from the DOS box, you could enter 
protected mode and go and trash memory while running at PL0. I don't
know of any DOS programs which enter protected mode via some "non-standard"
meathod, and I assume that INT15 Func 89H is disabled, but I have 
never checked this. I would also assume that you can trash the interrupt
vector table at 0:0 and kill the system too. This is a lot more likely
since all you need to do is write to a NULL far pointer. 
memcpy(NULL,foo,0x3FF) should trash the entire table. 

Cheers!
Steve



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        resnicks@netcom.com, steve@camphq, IFNA:        1:143/105.0, 
                 co moderator for comp.binaries.os2
 Real life: Steve Resnick. Chief Software Architect, Process Scientific, Inc
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