The GDB serial-line debugging protocol is probably the most powerful and commonly-used remote debugging protocol supported by GDB; this is the only protocol for which the OSKit currently has direct support. The GDB serial-line debugging stub supplied with the OSKit is fully architecture-independent, and supports most of the major features of the GDB serial-line protocol.
For technical information on the remote serial-line GDB debugging protocol, or information on how to run and use the remote debugger itself, consult the appropriate sections of the GDB manual. This section merely describes how remote serial-line debugging is supported by the OSKit.
Note that source code for several example serial-line debugging stubs are supplied in the GDB distribution (gdb/*-stub.c); in fact, this code was used as a template and example for the OSKit's serial-line debugging stub. However, these stubs are highly machine-dependent and make many more assumptions about how they are used. For example, they assume that they have exclusive control of the processor's trap vector table, and are therefore only generally usable in an embedded environment where traps are never supposed to occur during normal operation and therefore all traps can be fielded directly by the debugger. In contrast, the serial-line debugging stub provided in the OSKit is much more generic and cleanly decomposed, and therefore should be usable in a much wider range of environments.