Hello, I donŽt know very much about the i386-processor and Fiasco, therefore I would like to know if the following RMGR/Fiasco extensions are possible. 1) As default, no task has I/O port access. (CPL > IOPL or I/O permission bitmap pointer invalid) 2) A task asks via IPC the RMGR for I/O port access, e.g. port=0x80, length=4. 3) The RMGR checks, if port access can be granted. If yes, the RMGR decreases the tasks CPL and/or changes the tasks I/O permission bitmap. ==> Task is able to access port 0x80 - 0x83. The main question: I donŽt know if a task is able to change the CPL or the I/O permission bitmap of another task. Ciao, Christian -- -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Christian Stueble............stueble@ls6.cs.uni-dortmund.de PubKey[BF7104F5].......fp=8678C5D3CAD9CD8C F1DDB8EC202F116A To be or not to be is true... (apocrypha of George Boole) -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-