From: peter AT agnes DOT dida DOT physik DOT uni-essen DOT de (Peter Gerwinski)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: EMX, RSX, CWSDPMI, DJGPP trivia!
Date: 19 Jan 1997 21:28:41 GMT
Organization: Universitaet Essen, Germany
Lines: 56
Message-ID: <5bu3m9$3ko@sun3.uni-essen.de>
References: <01bc0263$7dac6840$7ccc5380 AT maan-m DOT -hamze>
Reply-To: peter DOT gerwinski AT uni-essen DOT de
NNTP-Posting-Host: agnes.dida.physik.uni-essen.de
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

Maan M. Hamze (mmhamze AT mail DOT utexas DOT edu) wrote:
> 1.  What is exactly EMX?

A DOS extender and a DLL for OS/2 simultaneously.  It is similar to
DJGPP since development is done with the GNU development tools.

> 2.  RSX is a DOS-extender too, so what is the difference between EMX and
> RSX?

A replacement for EMX which works with DPMI.  EMX, in contrast, does
not work when a DPMI host without VCPI is running.

> 3.  RSX, as used through RSXNT and NT09, needs a DPMI memory manager like
> CWSDPMI in DOS Mode.  But EMX
> does not.  What am I missing?  How are EMX, RSX and CWSDPMI related to one
> another?  (You do not need CWSDPMI with
> EMX, but you need it with RSX).

See above.  EMX is the DOS extender for non-DPMI systems, RSX for
DPMI systems, CWSDPMI is a DPMI host, i.e. it makes a DPMI system
out of a non-DPMI system. ;)

> 4.  What is the difference between the regular EMX port and DJGPP for DOS
> apps?  Is EMX a 16-bit dos-extender?

No, both are 32-bit.  They are two independend environments.

EMX advantage:  EXE files produced with EMX will run on DOS systems with 
EMX extender as well as on OS/2 systems with EMX library.

DJGPP advantage:  EXE files are standalone; they run on DOS systems with
DPMI; no further extender is necessary.

> Do EMX DOS apps run in real or protected mode?

Protected mode.

> And the last question:
> 5.  NT09 along with RSXNT can create DOS apps (dual mode for native win32;
> and DOS with RSX and a dpmi) as long as you use RSX with
> CWSDPMI in DOS.
> So my question is, is it possible to use Graphics and windowing libraries
> for DJGPP (such as grx, mikallig, mtws, and sound libs etc...)
> with the DOS apps created using RSXNT and NT09?

Probably not because DJGPP and EMX are two independent systems, but
it should not be too difficult to port programs between them.  I did
so for some GNU Pascal stuff.

Greetings,

    Peter

      e-mail:  peter DOT gerwinski AT uni-essen DOT de
home address:  D\"usseldorfer Str. 35, 45145 Essen, Germany
         WWW:  http://agnes.dida.physik.uni-essen.de/~peter/