The following is a list of possible faults causing entry to the Supervisor monitor program, with the fault heading, trap number, and mark or count in B91, in each case. For further explanations see CS 348A, Chapter 11.
Fault Monitor Printing Detected by Mark or count Trap No
in B91 (if any)
local time expired L TIME EXCEEDED S bit 5 0
division overflow DIV OVERFLOW I bit 6 1
exponent overflow EXP OVERFLOW I bit 14 2
page locked down PAGE LOCKED DOWN S bit 1 3
no. of blocks exceeded EXCESS BLOCKS S 2.0 4
square root argument < 0 SQ RT -VE ARC E 2.4 5
logarithm argument ≤ 0 LOG -VE ARG E 3.0 6
1/2" tape fault IBM TAPE ERROR E 3.4 7
inverse trig, function INVERSE TRIG OUT OF RANGE E 4.0 8
reading after input ended INPUT ENDED S 4.4 9
end of magnetic tape END TAPE S 5.0 10
variable length record error V TAPE ERROR E 5.4 11
magnetic tape failure TAPE FAIL S 6.0 12
computer failure COMPUTER FAIL S 6.4 13
unassigned function ILLEGAL FUNCTION I bit 4
sacred violation instr. SV INSTRUCTION I bit 8
sacred violation operand SV OPERAND I bit 10
illegal block no. ILLEGAL BLOCK S 9.6
band not reserved BAND NOT RESERVED S 10.2
computing time expired C TIME EXCEEDED S bit 2
execution time expired E TIME EXCEEDED S bit 3
input not defined INPUT NOT DEFINED S 11.6
output not defined OUTPUT NOT DEFINED S 12.2
output exceeded OUTPUT EXCEEDED S 12.6
tape not defined TAPE NOT DEFINED S 13.2
illegal search ILLEGAL SEARCH S 13.6
no selected tape NO TAPE SELECTED S 14.2
no mode defined, or attempt WRONG TAPE MODE S 14.6
to write when not permitted
no. of decks exceeded EXCESS DECKS S 15.2
no. of trap set TRAP UNSET S 15.6
no. of branches exceeded EXCESS BRANCHES S 16.2
(I = interrupt routine, E = extracode, S = Supervisor extracode routine)