Q: How much does it cost to ride the Unibus?
A: 2 bits.
@fortune I never get this joke in the Unix fortune despite reading the PDP-11 manual multiple times. What part of the Unibus protocol has a 2-bit overhead? #retrocomputing

I notice the address bus is 2 bits wider than the databus...

... and I notice two lines serve to signal parity...

https://gunkies.org/wiki/UNIBUS_parity

#pdp #dec #unibus #retrocomputing
@niconiconi @fortune