Interesting or Curious

• usr/src/cmd/audio/samples/au/Makefile There are audiofiles (or were) for the desktop environment, and one if them is a "doorbell".

• usr/src/cmd/bhyve/common/pci_nvme.c bhyve doorbells are a notification mechanism for VM guests, and they are unrelated to illumos doors. These doorbells also exist in the FreeBSD implementation of bhyve.

• usr/src/cmd/bhyve/common/pci_xhci.c Same as above.

• usr/src/contrib/bhyve/dev/nvme/nvme.h Same as above.

• usr/src/contrib/bhyve/dev/usb/controller/xhcireg.h Same as above.

• usr/src/cmd/bnu/Devices bnu devices mention something called a "garage/door" but this seems to be in the context of serial modems.

• usr/src/cmd/file/file.c The file(1) command uses door_info to print information about the cookie and associated door server, if possible. If the call to door_info fails, it just says "door".

• usr/src/cmd/initpkg/shutdown.sh The script for shutting down the system checks to see if SMF is running by checking wether its door rendezvous file (its "jamb") exists. No door_call is attempted.