Debugging Linux 0.11 on Windows with VSCode Remote and QEMU

Overview

Linux 0.11 is an early Linux kernel source useful for studying operating‑system fundamentals. It cannot be built with modern toolchains because it relies on the obsolete a.out format. The workflow runs the kernel inside QEMU on an Ubuntu 16.04 virtual machine and debugs from the host Windows machine via VSCode Remote‑SSH and GDB.

Step 1 – Configure the VM

Create an Ubuntu 16.04.7 desktop VM (amd64) using Oracle VM VirtualBox 6.0.8. Install the ISO from the Ubuntu releases page.

Step 2 – Install QEMU

Inside the Ubuntu VM run:

sudo apt-get update
sudo apt-get install qemu

Verify that qemu-system-x86_64 is available.

Step 3 – Obtain a debug‑ready Linux 0.11 source

Clone the community‑maintained repository that patches the code for modern compilers:

https://github.com/yuan-xy/Linux-0.11

In the top‑level directory run: make start This boots Linux 0.11 in QEMU. For debugging use: make debug The make debug target starts QEMU with a GDB server listening on port 1234.

Step 4 – Remote debugging with VSCode

Install Visual Studio Code on Windows and add the Remote‑SSH extension. Connect to the Ubuntu VM via its IP address, username and password. Open the Linux 0.11 source folder and create .vscode/launch.json with the following configuration:

{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "(gdb) Launch",
      "type": "cppdbg",
      "request": "launch",
      "program": "${workspaceFolder}/tools/system",
      "miDebuggerServerAddress": "127.0.0.1:1234",
      "args": [],
      "stopAtEntry": false,
      "cwd": "${workspaceFolder}",
      "environment": [],
      "externalConsole": false,
      "MIMode": "gdb"
    }
  ]
}

Start the kernel in debug mode inside the VM ( make debug), then in VSCode choose Run → Start Debugging . The debugger attaches to the QEMU‑hosted kernel, allowing breakpoints, step‑by‑step execution, and inspection of kernel state.

Alternative command‑line debugging

If you prefer a terminal, run GDB inside the VM and connect to the same server:

gdb tools/system
target remote :1234

Conclusion

The described setup isolates the heavy build and emulation inside an Ubuntu VM while providing a responsive host UI for editing and debugging. The same method can be applied to a remote server to avoid consuming local resources.