winscape 2247

Sigh! Not quite. Help, I don't think he's getting what I mean and I don't know how to tell him.

You're thinking like application programmer not an buttembly language coder.

This is how I worked when I had a system stand-alone. I would load a boot into core which is close to your equivalent to starting up your BIOS, but just starting. If DDT was loaded with this boot code, I could patch the boot code to do things, or fix things, or anything I wanted including redirecting which file I loaded as the monitor (core-resident piece of the OS).

Then, if DDT were loaded with the monitor, I could patch it set bits, do anything I wanted to that machine code before starting it. I could set breakpoints so that execustion would stop and wait for me to do something. At breakpoint, I could change any of the code, do more patching, execute a single instruction or a sub-routine. And then I could tell the debugger to proceed and the monitor would continue to run as if no interventions had happened until it hit another breakpoint or I told DDT to stop it.

I'm not talking about this level of abstraction at all.

nope. A CPU can only execute one instruction at a time. Multi-threading is how an OS decides which instruction to execute next and how the OS keeps track of different sets of code.

BAH