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study/sabre/os/files/ProtectedMode/PMODES.txt

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+ 
+  Greetings, Tran (a.k.a. Thomas Pytel) typing here. This bunch of files
+comprises two versions of my protected mode DOS extender PMODE. They are both
+publicly available and are not confidential or proprietary. I, Thomas Pytel,
+reserve all rights to the source code. However, feel free to use or distribute
+them in any manner you wish. All I ask, if you use this code in some
+production, is credits.
+
+  This package is meant mainly as an update for coders already using PMODE,
+But you can use it to start from scratch. The code and documentation may not
+be thoroughly clear, in this case if you need more examples get some of the
+other PMODE releases (like PMC or any demo source codes I have released) for
+more practical examples.
+
+------------------------------------------------------------------------------
+
+  PMODE v2.5 and PMODE v3.03 are provided here in the form of source code,
+along with various examples of their use. Why two versions? PMODE 2 is the
+predecessor to PMODE 3, but it is also slightly different in intended
+functionality. PMODE 2 is a dedicated ASM DOS extender, a protected mode
+system for game/demo code and other standalone programs. PMODE 3 is a more
+general purpose protected mode kernel, suitable for almost any protected mode
+need (high level language extender).
+
+  PMODE 3 can do what PMODE 2 does, in fact, I converted PMODE 2.4 to a shell
+which uses PMODE 3 as its kernel and it is included here. The drawback to this
+is that PMODE 3 gobbles up more low memory. PMODE 2 has proven itself quite
+stable through the time its been in use. It is a small, fast, stable, albeit
+a tad bit limited extender. There is no sense in trashing it just because
+something newer and cleaner (in source) has come along. Each version has its
+appropriate uses, it is up to you to decide.
+
+  The major difference between PMODE 2 and PMODE 3 is that PMODE 2 is a more
+complete system. It sets up 32bit execution and memory pools (low and high)
+and handles other minor nuances of going from the DOS command line to
+protected mode code and back. PMODE 3 is designed to be the low level end of
+a more complete system (such as PMC, an extender for Borland C++ 4.0 I did
+with it). Technically speaking, more can be done with PMODE 3. But I still
+suggest using PMODE 2 for games and demos (if you don't mind all ASM coding).
+It would be nice if someone out there used PMODE 3 in an extender for Watcom
+C++. I am not pursuing PMC because BC4 is just plain crap (though it is usable
+in some instances). Don't worry about using/supporting one version over the
+other. Taking code between two different protected mode systems is trivial
+compared to going from real mode to protected mode.
+
+------------------------------------------------------------------------------
+
+  The source, documentation, and appropriate examples are included for both
+versions of PMODE in their appropriate separate archives. The batch files
+which build the examples assume you have TASM and TLINK in your path.
+
+  One word of caution, QEMMs DPMI host QDPMI has serious problems with memory
+allocation, mode switching, and IRQs. Keep this in mind when testing stuff
+under it. If something screws up (usually gives you a QDPMI exception), try it
+with a different DPMI host.
+
+  TLINK also has problems with protected mode. Segment alignment has had its
+share of problems over time, as has referencing real mode segment addresses
+above the first 64k of a 32bit segment (fixup overflows).
+
+  This package is dated as of the beginning of September of 1994. Enjoy
+protected mode. You can send me mail (but don't expect a response, it is not
+possible due to account restrictions) at tran@phantom.com, so don't bother...
+
+                                        Oh well...
+                                        Tran...
+