Groups > comp.os.msdos.programmer > #1372

Re: detecting emulation or console windows

From	Ross Ridge <rridge@csclub.uwaterloo.ca>
Newsgroups	alt.os.development, comp.os.msdos.programmer, alt.lang.asm
Subject	Re: detecting emulation or console windows
Date	2014-06-01 14:03 -0400
Organization	University of Waterloo
Message-ID	<lmfptf$kuh$1@rumours.uwaterloo.ca> (permalink)
References	<op.xgqwuvss6zenlw@localhost> <lmdqcl$1oj$1@rumours.uwaterloo.ca> <op.xgq3g0ya6zenlw@localhost>

Cross-posted to 3 groups.

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Rod Pemberton <dont_use_email@xnothavet.cqm> wrote:
>IMO, CR0.PE should be emulated as _set_ for dosemu since dosemu provides
>it's own 32-bit PM DPMI host.  I.e., dosemu should report as PM, meaning
>v86 instead of RM.  However, it doesn't until something uses DPMI.

No, under bare-metal MS-DOS a DPMI host wouldn't normally switch into
protected mode until it was first used.  The processor wouldn't be
running in Virtual 8086 mode (CR0.PE set) unless something else like a
EMS emulator (eg. EMM386) put in that mode.

>The problem isn't the code.  It's a standard 32-bit PM DPMI (GCC via DJGPP)
>application with a 16-bit RM startup.  The problem is that the code
>basically runs everywhere, including under environments where it
>shouldn't be  executed, such as under OSes like Windows 98/SE/NT/2K/XP,
>and emulation such as  DOSBox and dosemu.  So, I'd like to detect and
>reject these environments.  The  other option is to just let the user
>try and fail.

Sorry, but I don't understand what the problem is.  Why exactly shouldn't
this code run under DOSBox or any other emulator that is designed
to emulate an entire PC, including real-mode and all hardware?  If it
crashes on DOSBox, but works fine on bare-metal MS-DOS then something is
either wrong with DOSBox or your application.  As far your application
is concerned it should startup in 16-bit real-mode and then switch in
32-bit protected mode via a DPMI host regardless of whether it's running
natively on an Intel CPU, software emulation using DOSBox or hardware
emulation running under Virtual PC, VirutalBox or some other VM.

Which brings up the fact that you haven't mentioned need to block your
code running under any of the VMs.  If you need to block it running on
software emulatorl like DOSBox you should also need to block it running
under hardware emulation.  If on the other hand your code works fine
under VMs but not DOSBox then this points back to this either being a
problem with your code or DOSBox.

I think maybe going about this the wrong way.  Perhaps the best way to
resolve your problem isn't to crudely detect incompatible environments,
but to detect whether the hardware or other specific minimal set of
conditions necessary for your program to run correctly are present.
You might also be able to make your application more robust so that it
doesn't crash when the enviroment isn't exactly what you need.

					Ross Ridge

-- 
 l/  //	  Ross Ridge -- The Great HTMU
[oo][oo]  rridge@csclub.uwaterloo.ca
-()-/()/  http://www.csclub.uwaterloo.ca/~rridge/ 
 db  //

Thread

detecting emulation or console windows "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-05-31 18:31 -0400
  Re: detecting emulation or console windows Ross Ridge <rridge@csclub.uwaterloo.ca> - 2014-05-31 19:59 -0400
    Re: detecting emulation or console windows "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-05-31 20:54 -0400
      Re: detecting emulation or console windows "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-05-31 21:43 -0400
        Re: detecting emulation or console windows "James Harris" <james.harris.1@gmail.com> - 2014-06-01 22:48 +0100
          Re: detecting emulation or console windows "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-06-02 00:46 -0400
            Re: detecting emulation or console windows "James Harris" <james.harris.1@gmail.com> - 2014-06-02 06:15 +0100
              Re: detecting emulation or console windows "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-06-02 03:21 -0400
                Re: detecting emulation or console windows "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-06-02 03:32 -0400
                Re: detecting emulation or console windows "James Harris" <james.harris.1@gmail.com> - 2014-06-02 09:51 +0100
                Re: detecting emulation or console windows "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-06-02 09:27 -0400
                Re: detecting emulation or console windows "James Harris" <james.harris.1@gmail.com> - 2014-06-02 17:05 +0100
                Re: detecting emulation or console windows "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-06-02 19:25 -0400
                Re: detecting emulation or console windows "James Harris" <james.harris.1@gmail.com> - 2014-06-04 07:55 +0100
                Re: detecting emulation or console windows "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-06-04 03:20 -0400
      Re: detecting emulation or console windows Ross Ridge <rridge@csclub.uwaterloo.ca> - 2014-06-01 14:03 -0400
        Re: detecting emulation or console windows "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-06-02 00:53 -0400
          Re: detecting emulation or console windows Ross Ridge <rridge@csclub.uwaterloo.ca> - 2014-06-02 15:55 -0400
            Re: detecting emulation or console windows "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-06-02 19:27 -0400
              Re: detecting emulation or console windows Ross Ridge <rridge@csclub.uwaterloo.ca> - 2014-06-03 17:00 -0400
  Re: detecting emulation or console windows Sjouke Burry <burrynulnulfour@ppllaanneett.nnll> - 2014-06-01 06:25 +0200
    Re: detecting emulation or console windows "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-06-01 02:50 -0400
  Re: detecting emulation or console windows "James Harris" <james.harris.1@gmail.com> - 2014-06-01 07:53 +0100
    Re: detecting emulation or console windows "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-06-01 04:53 -0400
      Re: detecting emulation or console windows "James Harris" <james.harris.1@gmail.com> - 2014-06-01 20:57 +0100
        Re: detecting emulation or console windows "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-06-02 00:48 -0400
      Re: detecting emulation or console windows "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-06-02 03:20 -0400
  Re: detecting emulation or console windows JJ <duh@nah.meh> - 2014-06-02 03:43 +0700
    Re: detecting emulation or console windows "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-06-02 00:34 -0400
    Re: detecting emulation or console windows "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-06-03 07:06 -0400
      Re: detecting emulation or console windows JJ <duh@nah.meh> - 2014-06-03 20:25 +0700
  Re: detecting emulation or console windows "wolfgang kern" <nowhere@never.at> - 2014-06-03 20:52 +0200
  Re: detecting emulation or console windows "James Harris" <james.harris.1@gmail.com> - 2014-06-03 22:59 +0100
    Re: detecting emulation or console windows CN <qmbmnp3799@pacbell.net> - 2014-06-03 18:39 -0700
      Re: detecting emulation or console windows "James Harris" <james.harris.1@gmail.com> - 2014-06-04 07:06 +0100
        Re: detecting emulation or console windows "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-06-04 03:07 -0400
          Re: detecting emulation or console windows "James Harris" <james.harris.1@gmail.com> - 2014-06-04 09:16 +0100
  Re: detecting emulation or console windows "James Harris" <james.harris.1@gmail.com> - 2014-06-03 23:00 +0100
  Re: detecting emulation or console windows "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-06-10 17:37 -0400
    Re: detecting emulation or console windows Wildman <best_lay@yahoo.com> - 2014-06-11 00:37 +0000
      Re: detecting emulation or console windows "Rod Pemberton" <dont_use_email@xnothavet.cqm> - 2014-07-27 12:11 -0400

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