JOBDAT as of 9 Jan 78:	
.JBUUO	 40	User's UUO data location; opcode and EA stored here
.JB41	 41	User's UUO trap address; contains instruction to go
		to user's trap routine (usually JSR or PUSHJ)
.JBERR	 42	LH: unused		RH: accumulated error count
.JBREL	 44	LH: 0			RH: highest lowseg address
.JBBLT	 45	three locations used by the loader and monitor
.JBDDT	 74	LH: Last addres of DDT	RH: Starting address of DDT
		if 0, DDT is not loaded
.JBHRL	115	LH: length of hiseg	RH: highest legal address in
					    hiseg, 0 => no hiseg
.JBSYM	116	LH: Negative length of	RH: Base address of symbol table
		    symbol table
.JBUSY	117	Same format as .JBSYM, pointer to undefined symbol table
.JBSA	120	LH: Initial .JBFF value	RH: Start address
.JBFF	121	LH: 0			RH: Address of first free location
					    in lowseg; set to .JBSA<18,18>
					    by RESET UUO
.JBREN	124	LH: Unused		RH: REENTER start address
.JBAPR	125	LH: 0			RH: Trap address for APR traps
.JBCNI	126	APR status from CONI when APR trap taken
.JBTPC	127	PC of next instruction when APR trap taken
.JBOPC	130	Previous .JOBPC saved by DDT, REENTER, START or CSTART
		In some cases this value points to the erroneous UUO, 
		see the reference manual.
.JBCHN	131	LH: 0 or first free loc	RH: Address of first location
		    after FORTRAN IV	    after first FORTRAN IV
		    program		    BLOCK DATA program
.JBCOR	133	LH: Highest location	RH: User core argument on
		    in lowseg loaded	    last GET or SAVE command
		    with nonzero data
.JBINT	134	LH: reserved		RH: 0 or address of error
					    intercept block
.JBVER	137	Version number: in octal, it is given as
		gVVVmm,,eeeeee
		where
		   g is the group who last modified the program:
			0 - DEC development
			1 - DEC
			2,3,4 - Customers
			5,6,7 - Customer's users
		  Mostly CMU ignores this field

		VVV major version number, in octal
		mm  minor version number.
			00 => no minor version
			01 => A
			02 => B etc.
		eeeeee edit level
			prints as (eeeeee)

		e.g., the .JBVER version number 103402,,4556
		would print to the VERSION command as 34B(4556)-1
NOTE: if the program has ONLY a high segment, .JBHVR must be set also!

For jobs with only a high segment, the vestigial job data area
is defined as the first '10 locations of the high segment, and
the fields are (relative to .JBHGH, usually 400000):

.JBHSA	 0	Copy of .JBSA
.JBH41	 1	Copy of .JB41
.JBHCR	 2	Copy of .JBCOR
.JBHRN	 3	LH: restores LH of .JBHRL
		RH: restores RH of .JBREN
.JBHVR	 4	Copy of .JBVER
.JBHNM	 5	High-segment name set on a SAVE (sixbit)
.JBHSM	 6	Pointer to highsegment symbols, if any
	 7	Reserved
.JBHDA	10	First free location after vestigial job data area