Tried installing Debian 8 or 9 with 128MB a while ago. The installer warned that this wouldn't be enough to finish setup, and sure enough, during installation the OOM killer got in the way. I restarted the installer, spawned a shell and killed some processes that looked non-essential, and this time I managed to finish. Using the actual system was obviously slow given two 233MHz CPUs, but even X11 with i3 worked. I then used it as a secondary screen via VNC. For about an hour. Then I shoved the machine back into the basement.