CompuServe Messages

David, Yes and no. ABI stands for Application Binary Interface. Thus, as you say, an ABI compliant program compiled on a 68k machine should run on any other ABI compliant 68k machine as is. However, part of the interface spec is that is uses "generic" system calls (calls that run in kernel mode and "hit the hardware") and the kernel code takes care of all the specifics of the hardware. Thus code is not written for a specific CPU, only compiled on a specific CPU. The code should also run on any other ABI compliant machine (with a different CPU) by simply re-compiling the code on a machine with the new type of CPU. The source code should be totally hardware independent as all the niggling details of hardware differences should be taken care of in the kernel interface. As a very simple example, that already is application independent, an open() call looks the same on a 486 machine as it does on a 68k machine. The code in the kernel that does the actual open of a file or device would be different though. Don