The OS/2 subsystem is being developed to enable NT-like systems (like WinNT - and ReactOS) to run 32-Bit OS/2 applications natively. With this it shall provide - binary compatiblility on x86-Based systems. It is intended to port the ROS/2 - also to other platforms supported by ReactOS / NT. It is planned to provide - source code compatibility on these platforms. Yeeahh, OS/2 for PowerPC is in - sight.
-ROS/2 consists of the following components:
-Up to now just a fragment of DOSCALLS.DLL exists. The biggest problem are the - os2 API headers which are (C) by IBM. So help is still welcome.
-It is not intended to support 16-bit OS/2 applications. This would make the - system inconsistent and produce much more work that use. But there is still - one issue: Current textmode applications are either 16-bit or use thunking to - call the 16-bit APIs. These 32-Bit thunking applications have to be supported. - We are still thinking how to accomplish that.
-It is planned to replace the current MOU- KBD- MSG- and VIO- subsystems with - the Unicode - Console API. This is also the foundation for other platforms we want to - provide source code compatibility with. So nearly every 32-Bit processor can - be supported. It sould even be possible to implement a 64-bit OS/2 API.
-To understand the architecture of ReactOS or WinNT read a book from the "Inside
- Windows NT"-series. The architecture of ROS/2 is like every normal subsystem.
- When OS2SS.EXE starts, it creates an object directory named os2 and therein
- it creates a port object with the name Os2API. A port is something like a socket.
- Two programs can comunicate with each other via a port. The port Os2API provides
- the LPC API of the OS2SS.EXE - the actual subsystem.
- Every OS/2 program that is loaded, is linked with DOSCALLS.DLL and NTDLL.DLL
- - the interface to the NT-kernel. Since DOSCALLS is implemented using NTDLL.DLL,
- every OS/2 app has it in its adress space. Many functions in DOSCALLS.DLL are
- implemented by just wrapping NTDLL.DLL functions. Some functions however need
- assistance by the subsystem. For this reason the app makes an LPC to OS2SS.EXE.
- LPC means local procedure call and it is a very fast version of RPC. Together
- with the first application also OS2.EXE starts up. OS2.EXE runs in the win32
- subsystem with the security of the current user. OS2.EXE is used to gather keyboard
- and mouse input and to show console windows and PM-windows of all OS/2 programms
- of the current user. In order to accomplish this OS2.EXE creates a port object
- in the os2 object directory named Os2Interact. OS/2 applications have a connection
- to OS2.EXE, too. OS2SS.EXE and OS2.EXE also talk to each other. An OS/2 application
- then makes LPCs either to OS2.EXE directly or if required via OS2SS.EXE.
Details
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LPC Documentation
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