rd(4) on OpenBSD
The text 64f69b02ad22, as OpenBSD 6.5, OpenBSD 6.4, OpenBSD 6.3, OpenBSD 6.2, OpenBSD 6.1, OpenBSD 6.0, OpenBSD 5.9, OpenBSD 5.8, OpenBSD 5.7, OpenBSD 5.6, OpenBSD 5.5 shipped it.
ramdisk driver
The text 64f69b02ad22, as OpenBSD 6.5, OpenBSD 6.4, OpenBSD 6.3, OpenBSD 6.2, OpenBSD 6.1, OpenBSD 6.0, OpenBSD 5.9, OpenBSD 5.8, OpenBSD 5.7, OpenBSD 5.6, OpenBSD 5.5 shipped it.
ramdisk driver