I've been doing operating system development (not building a Linux kernel), and have gotten to the point where I need a debugger, for my latest OS. I've tried Bochs (under my Win 7 partition), but that wouldn't recognize my USB (It's unformatted, I'm reading specific sectors right now.) and I would rather do something under Ubuntu 11.10.
Is there a Debugger that would let me debug a custom build OS for Ubuntu 11.10?
Personally, I use QEMU for debugging a custom OS (which has USB support).
Run QEMU as follows for a debugging session:
qemu -S -s [more options here]
-S
tells QEMU to not start the cpu. This gives you time to set breakpoints etc.
-s
is a shortcut for -gdb tcp::1234
which start a gdbserver at TCP port 1234.
Then connect GDB to QEMU:
$ gdb
(gdb) target remote localhost:1234
From that point, you can use the normal GDB commands.