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Re: Changing a DPMI host, but keeping the DOS extender

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Rod Pemberton <do_not_have@notemailntt.cmm> wrote:
>The other day I had this thought:
>
>  "I wish I could keep this DPMI host's DOS extender,
>    but change it's DPMI host..."
>
>That would be useful to me.  The issue I'm seeing is that if I start a DPMI
>host with a DOS extender, and then start a DPMI host without a DOS extender,
>both as single use, each runs and exits separately of the other.  That
>indicates to me both are installed, but neither is activated until a DPMI
>program activates DPMI.

Well, DPMI can't really be running while you're using MS-DOS, since
DPMI provides a protected mode enviroment and MS-DOS runs in real mode.
It's going to have to sit around waiting for some application to request
the use of services before switching to protected mode and actually
providing DPMI functionality.

Note that a DOS extender doesn't necessarily need to use DPMI.  DPMI is
designed to handle the case where some other operating system is emulating
MS-DOS in virtual 8086 mode and doesn't want give up full control of the
CPU.  Many DOS extenders were designed to switch into protected mode from
real mode directly and only fell back on DPMI when that wasn't possible.

Somewhat complicating the issue is that memory managers like EMM386
would switch the CPU into virtual 8086 mode in order implement EMS memory
and UMBs.  In this case DOS extenders would use VCPI to gain full control
of the CPU and switch into protected mode.

>Of course, I'm trying to get *merged* or *replaced*
>functionality, i.e., the DPMI host without the DOS extender to replace the
>DPMI functionality of the DPMI host with DOS extender.

You might get better luck if you start the DPMI host before running the
DOS extended application.

					Ross Ridge

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

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Thread

Changing a DPMI host, but keeping the DOS extender "Rod Pemberton" <do_not_have@notemailntt.cmm> - 2012-05-19 20:08 -0400
  Re: Changing a DPMI host, but keeping the DOS extender Rugxulo <rugxulo@gmail.com> - 2012-05-19 19:07 -0700
    Re: Changing a DPMI host, but keeping the DOS extender "Rod Pemberton" <do_not_have@notemailntt.cmm> - 2012-05-20 05:38 -0400
      Re: Changing a DPMI host, but keeping the DOS extender Rugxulo <rugxulo@gmail.com> - 2012-05-20 09:15 -0700
        Re: Changing a DPMI host, but keeping the DOS extender "Rod Pemberton" <do_not_have@notemailntt.cmm> - 2012-05-20 20:46 -0400
          Re: Changing a DPMI host, but keeping the DOS extender Rugxulo <rugxulo@gmail.com> - 2012-05-21 16:26 -0700
            Re: Changing a DPMI host, but keeping the DOS extender "Rod Pemberton" <do_not_have@notemailntt.cmm> - 2012-05-22 03:39 -0400
              Re: Changing a DPMI host, but keeping the DOS extender Rugxulo <rugxulo@gmail.com> - 2012-05-22 08:41 -0700
                Re: Changing a DPMI host, but keeping the DOS extender Rugxulo <rugxulo@gmail.com> - 2012-05-22 16:14 -0700
                Re: Changing a DPMI host, but keeping the DOS extender "Rod Pemberton" <do_not_have@notemailntt.cmm> - 2012-05-24 15:38 -0400
                Re: Changing a DPMI host, but keeping the DOS extender Rugxulo <rugxulo@gmail.com> - 2012-05-24 14:06 -0700
                Re: Changing a DPMI host, but keeping the DOS extender Ross Ridge <rridge@csclub.uwaterloo.ca> - 2012-05-25 02:14 -0400
                Re: Changing a DPMI host, but keeping the DOS extender Rugxulo <rugxulo@gmail.com> - 2012-05-25 15:55 -0700
                Re: Changing a DPMI host, but keeping the DOS extender Ross Ridge <rridge@csclub.uwaterloo.ca> - 2012-05-25 21:42 -0400
                Re: Changing a DPMI host, but keeping the DOS extender Ross Ridge <rridge@csclub.uwaterloo.ca> - 2012-05-25 22:06 -0400
                Re: Changing a DPMI host, but keeping the DOS extender Rugxulo <rugxulo@gmail.com> - 2012-05-25 23:03 -0700
                Re: Changing a DPMI host, but keeping the DOS extender "Rod Pemberton" <do_not_have@notemailntt.cmm> - 2012-05-26 07:33 -0400
                Re: Changing a DPMI host, but keeping the DOS extender Ross Ridge <rridge@csclub.uwaterloo.ca> - 2012-05-26 20:10 -0400
                Re: Changing a DPMI host, but keeping the DOS extender "Harry Vaderchi" <admin@127.0.0.1> - 2012-05-28 07:38 +0100
  Re: Changing a DPMI host, but keeping the DOS extender Ross Ridge <rridge@csclub.uwaterloo.ca> - 2012-05-20 19:20 -0400

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