2.11BSD Device Names

David Coolbear david at thecoolbears.org
Thu Sep 15 15:08:06 CDT 2016

For 2.11BSD on the PDP-11, in the stand alone utilities that are found on
the installation tape, the storage devices are named:

dn(x,y,z) where dn is the mnemonic for the driver, x is the controller
number, y is the unit number and z is the partition on the unit. So the
first partition on the first drive on the first MSCP controller is
ra(0,0,0). It's fairly easy form the install tape to disklabel and mkfs a
drive on a second controller.

Once UNIX is running, things change. The devices in /dev are named ra0 for
the first unit on the first controller, ra1 for the second unit on the
first controller and etc. I don't see a way in the naming convention to
identify other controllers.

My question is, what is the device name in /dev for the first drive on the
second controller?

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