Okay, let's see. The user is reporting that Ctrl-A b isn't working in QEMU 2.8.0, but it worked in 2.7.0. They're using NetBSD amd64, and they built QEMU from source. The problem is that sending a break to the VM isn't working anymore. Other Ctrl-A sequences work, so it's specific to the 'b' command. First, I need to figure out what category this falls into. The options are instruction, syscall, or runtime. An instruction bug would be related to specific CPU instructions being executed incorrectly. A syscall error would involve system calls made by QEMU to the host OS. Runtime errors are other issues that occur during execution, not necessarily tied to specific instructions or syscalls. The Ctrl-A b sequence is a key combination used in QEMU's monitor to send a break signal to the virtual machine. This is part of the user interaction handling. Since the user mentions that other Ctrl-A sequences work, it's likely a problem with how QEMU 2.8.0 handles this specific key combination. I don't think this is a faulty instruction. The issue is more likely related to how the input is processed, which is part of the runtime behavior. There's no indication that a specific syscall is failing here. The problem seems to be in the code that maps the key combination to the action, which would be a runtime error. So the category should be 'runtime'. runtime