Some further info on the parity halt/trap thing:
Digging again this morning for what I saw yesterday, it does look like it's a
MS11 fastbus thing. The EHA/EHB bits are described in the Jan 1973 version of
the 11/45 MS11 maintenance manual (table 3-12, describing the parity register),
but they have been scrubbed out by the time of the Jan 1974 printing of the
same manual!
Somewhere yesterday I saw an actual register layout drawing that had these
bits, but I'm not able to find it again this afternoon so far...
--FritzM.
