it is a combination of pins for the Qbus, pins for the DSSI on the 
backplane, power, and the memory interconnect. It is unique to these 
machines, i dont remember the name for it but it is just some boring name
as part of a vax4000/[4567]00 processor, nothing more. 

> 
> What bus are these?  I saw a cpu on ebay and it did not look like
> Qbus.  It it Mbus or something strange?
>