DEC made diagnostic procedures for all of their hardware, here we concentrate on the PDP-11 universe.

Many of these diagnostics are on the web today, but widely scattered around. 

They have several designations, come on several media, are made for different devices, run under several supervisor monitors and are separated from their documentiation.

So here is a try to pull all pieces together and order them into one system:

The PDP-11 Diagnostics Database