DCB for BDAM

Common Name:

Data Control Block for BDAM

Macro Name:

DCBD

DSECT Name:

IHADCB

Owning Component:

Data Management, subcomponent OPEN/CLOSE/EOV

Eye-Catcher ID:

None

Subpool and Key:

Problem program subpool and key

Size:

104 bytes

Created by:

Problem program

Pointed to by:

DEBDCBAD field of the DEB data area
IOBDCBPT field of the IOB data area
DECDCBAD field of the DECB data area

Serialization:

The user is responsible for serialization. While OPEN/CLOSE processes the DCB, a temporary protected copy of the DCB is made to serialize processing. Use the DEBCHK macro to check for the validity of the DCB.

Function:

This data control block (DCB) contains information pertaining to the data sets being processed by the basic direct access method (BDAM) routines. All DCB formats share the same interface and foundation sections. The direct access storage device (DASD) section and the BDAM interface section complete the description of the block.

Offset	Type/Value	Len	Name (Dim)	Description
DATA CONTROL BLOCK DEFINITION
	X'80'		DCBBIT0	"128"
	X'40'		DCBBIT1	"64"
	X'20'		DCBBIT2	"32"
	X'10'		DCBBIT3	"16"
	X'8'		DCBBIT4	"8"
	X'4'		DCBBIT5	"4"
	X'2'		DCBBIT6	"2"
	X'1'		DCBBIT7	"1"
ACCESS METHOD COMMON INTERFACE
16 (10)	SIGNED	4	DCBRELB (0)	–SAME AS DCBREL BELOW
16 (10)	SIGNED	1	DCBKEYLE	–KEY LENGTH OF DATA SET
17 (11)	CHARACTER	1	DCBDEVT (0)	– DEVICE TYPE
	.1. . 1111		DCBDVTRM	"X'4F'"– TERMINAL. (DD CONTAINS TERM=TS)
17 (11)	SIGNED	3	DCBREL	–NUMBER OF RELATIVE TRACKS OR BLOCKS IN THIS DATA SET (BDAM)
20 (14)	ADDRESS	4	DCBBUFCB (0)	–ADDRESS OF BUFFER POOL CONTROL BLOCK
20 (14)	SIGNED	1	DCBBUFNO	– NUMBER OF BUFFERS REQUIRED FOR THIS DATA SET. MAY RANGE FROM 0 TO 255. IF UNBLOCKED SPANNED RECORDS ARE USED, NUMBER OF SEGMENT WORK AREAS REQUIRED FOR THIS DATA SET.
21 (15)	ADDRESS	3	DCBBUFCA	-ADDRESS OF BUFFER POOL CONTROL BLOCK
24 (18)	SIGNED	2	DCBBUFL	–LENGTH OF BUFFER. MAY RANGE FROM 0 TO 32,767.
26 (1A)	BITSTRING	2	DCBDSORG (0)	–DATA SET ORGANIZATION BEING USED
26 (1A)	BITSTRING	1	DCBDSRG1	–FIRST BYTE OF DCBDSORG
	1. . . . . . .		DCBDSGIS	"DCBBIT0"– IS – INDEXED SEQUENTIAL ORGANIZATION
	.1. . . . . .		DCBDSGPS	"DCBBIT1"– PS – PHYSICAL SEQUENTIAL ORGANIZATION
	. .1. . . . .		DCBDSGDA	"DCBBIT2"– DA – DIRECT ORGANIZATION
	. . .1 . . . .		DCBDSGCX	"DCBBIT3"– CX – BTAM OR QTAM LINE GROUP
	. . . . . .1.		DCBDSGPO	"DCBBIT6"– PO – PARTITIONED ORGANIZATION
	. . . . . . .1		DCBDSGU	"DCBBIT7"– U – UNMOVABLE, THE DATA CONTAINS LOCATION DEPENDENT INFORMATION
27 (1B)	BITSTRING	1	DCBDSRG2	–BYTE OF DCBDSORG
	1. . . . . . .		DCBDSGGS	"DCBBIT0"– GS – GRAPHICS ORGANIZATION
	.1. . . . . .		DCBDSGTX	RESERVED
	. .1. . . . .		DCBDSGTQ	RESERVED
	. . . . 1. . .		DCBACBM	"DCBBIT4"– ACCESS METHOD CONTROL BLOCK
	. . . . .1. .		DCBDSGTR	RESERVED
28 (1C)	ADDRESS	4	DCBIOBAD (0)	ADDRRESS OF IOB. SET WITH CHAINED SCHEDULING OR OPTIONALLY WHEN EXCP IS USED.
28 (1C)	ADDRESS	4	DCBICQE (0)	–ADDRESS OF ICQE
28 (1C)	ADDRESS	4	DCBODEB (0)	–ADDRESS OF OLD DEB
28 (1C)	SIGNED	1	DCBLNP (0)	–3525 PRINTER LINE POSITION COUNTER
28 (1C)	BITSTRING	1	DCBQSLM	–QSAM LOCATE MODE LOGICAL RECORD INTERFACE INDICATOR BYTE FOR UPDAT PROCESSING OF SPANNED RECORDS
	1. . . . . . .		DCB1DVDS	"DCBBIT0"– ONLY ONE DEVICE IS ALLOCATED TO THIS DATA SET
	.1. . . . . .		DCBUPDCM	"DCBBIT1"– UPDATE COMPLETE, FREE OLD DEB
	. .11 . . . .		DCBUPDBT	"DCBBIT2+DCBBIT3"– UPDATE BITS
	. .1. . . . .		DCBUPDT	"DCBBIT2"– UPDATE TO TAKE PLACE
	. .11 . . . .		DCBNUPD	"DCBBIT2+DCBBIT3"– NO UPDATE TO TAKE PLACE
	. . .1 . . . .		DCBSVDEB	"DCBBIT3"– OLD DEB ADDRESS MUST BE SAVED
29 (1D)	ADDRESS	3	DCBIOBAA (0)	– SAME AS DCBIOBAD ABOVE
29 (1D)	ADDRESS	3	DCBICQEA (0)	– SAME AS DCBICQE ABOVE
29 (1D)	ADDRESS	3	DCBODEBA	- ADDRESS OF OLD DEB
28 (1C)	ADDRESS	4	DCBSVCXL (0)	– SAME AS DCBSVCXA BELOW
28 (1C)	BITSTRING	1		– RESERVED
29 (1D)	ADDRESS	3	DCBSVCXA	– POINTER TO EXIT LIST OF JES C.I. INTERFACE CONTROL SVC
FOUNDATION EXTENSION
32 (20)	ADDRESS	4	DCBEODAD (0)	– SAME AS DCBEODA BELOW
32 (20)	BITSTRING	1	DCBHIARC (0)	– HIERARCHY BITS
32 (20)	BITSTRING	1	DCBBFTEK (0)	– BUFFERING TECHNIQUE BITS
32 (20)	BITSTRING	1	DCBBFALN	– BUFFER ALIGNMENT BITS
	1. . . . . . .		DCBH1	"DCBBIT0"– HIERARCHY 1 MAIN STORAGE – BIT 5 IS ZERO
	.111 . . . .		DCBBFT	"DCBBIT1+DCBBIT2+DCBBIT3" BUFFERING TECHNIQUE
	.11. . . . .		DCBBFTA	"DCBBIT1+DCBBIT2" – QSAM LOCATE MODE PROCESSING OF SPANNED RECORDS – OPEN IS TO CONSTRUCT A RECORD AREA IF IT AUTOMATICALLY CONSTRUCTS BUFFERS
	. .1. . . . .		DCBBFTR	"DCBBIT2"– FOR BSAM CREATE BDAM PROCESSING OF UNBLOCKED SPANNED RECORDS – SOFTWARE TRACK OVERFLOW. FOR BSAM INPUT PROCESSING OF UNBLOCKED SPANNED RECORDS WITH KEYS – RECORD OFFSET PROCESSING.
	.1. . . . . .		DCBBFTS	"DCBBIT1"– SIMPLE BUFFERING – BIT 3 IS ZERO
	. .1. . . . .		DCBBFTKR	"DCBBIT2"– UNBLOCKED SPANNED RECORDS – SOFTWARE TRACK OVERFLOW (BDAM)
	. . .1 . . . .		DCBBFTE	"DCBBIT3"– EXCHANGE BUFFERING – BIT 1 IS ZERO
	. . . . 1. . .		DCBBFTKD	"DCBBIT4"– DYNAMIC BUFFERING (BTAM)
	. . . . 1. . .		DCBBFTK	"DCBBIT4"– LRECL IN 'K' UNITS FOR XLRI
	.11. 1. . .		DCBBXLRI	"DCBBIT1+DCBBIT2+DCBBIT4" – EXTENDED LOGICAL RECORD INTERFACE MODE FOR SPANNED RECORDS GREATER THAN 32K – ALL RECORDS TRANSFERRED TO OR FROM THE RECORD AREA.
	. . . . .1. .		DCBH0	"DCBBIT5"– HIERARCHY 0 MAIN STORAGE – BIT 0 IS ZERO
	. . . . . .11		DCBBFA	"DCBBIT6+DCBBIT7"– BUFFER ALIGNMENT
	. . . . . .1.		DCBBFAD	"DCBBIT6"– DOUBLEWORD BOUNDARY
	. . . . . . .1		DCBBFAF1	"DCBBIT7"– FULLWORD NOT A DOUBLEWORD BOUNDARY, CODED IN DCB MACRO INSTRUCTION
	. . . . . .11		DCBBFAF2	"DCBBIT6+DCBBIT7"– FULLWORD NOT A DOUBLEWORD BOUNDARY, CODED IN DCB MACRO INSTRUCTION
33 (21)	ADDRESS	3	DCBEODA	– ADDRESS OF A USER–PROVIDED ROUTINE TO HANDLE END–OF7–DATA CONDITIONS
36 (24)	ADDRESS	4	DCBEXLST(0)	– ADDRESS OF USER-PROVIDED LIST OF EXITS
36 (24)	BITSTRING	1	DCBRECFM	– RECORD FORMAT
	111. . . . .		DCBRECLA	"DCBBIT0+DCBBIT1+DCBBIT2" RECORD LENGTH INDICATOR – ASCII
	. .1. . . . .		DCBRECD	"DCBBIT2"– ASCII VARIABLE RECORD LENGTH
	11. . . . . .		DCBRECL	"DCBBIT0+DCBBIT1"– RECORD LENGTH INDICATOR
	1. . . . . . .		DCBRECF	"DCBBIT0"– FIXED RECORD LENGTH
	.1. . . . . .		DCBRECV	"DCBBIT1"– VARIABLE RECORD LENGTH
	11. . . . . .		DCBRECU	"DCBBIT0+DCBBIT1"– UNDEFINED RECORD LENGTH
	. .1. . . . .		DCBRECTO	"DCBBIT2"– TRACK OVERFLOW
	. . .1 . . . .		DCBRECBR	"DCBBIT3"– BLOCKED RECORDS
	. . . . 1. . .		DCBRECSB	"DCBBIT4"–FOR FIXED LENGTH RECORD FORMAT – STANDARD BLOCKS. FOR VARIABLE LENGTH RECORD FORMAT – SPANNED RECORDS
	. . . . .11.		DCBRECCC	"DCBBIT5+DCBBIT6"– CONTROL CHARACTER INDICATOR
	. . . . .1. .		DCBRECCA	"DCBBIT5"– ASA CONTROL CHARACTER
	. . . . . .1.		DCBRECCM	"DCBBIT6"– MACHINE CONTROL CHARACTER
	. . . . . . . .		DCBRECC	"X'00'"– NO CONTROL CHARACTER
	. . . . . . .1		DCBRECKL	"DCBBIT7"– KEY LENGTH (KEYLEN) WAS SPECIFIED IN DCB MACRO INSTRUCTION
37 (25)	ADDRESS	3	DCBEXLSA	– ADDRESS OF USER-PROVIDED LIST OF EXITS
FOUNDATION BEFORE OPEN
40 (28)	CHARACTER	8	DCBDDNAM	– NAME ON THE DD STATEMENT WHICH DEFINES THE DATA SET ASSOCIATED WITH THIS DCB
48 (30)	BITSTRING	1	DCBOFLGS	– FLAGS USED BY OPEN ROUTINE
	1. . . . . . .		DCBOFLWR	"DCBBIT0"– IF ZERO, LAST I/O OPERATION WAS READ OR POINT. IF ONE, LAST I/O OPERATION WAS WRITE.
	1. . . . . . .		DCBOFIOD	"DCBBIT0"– DATA SET IS BEING OPENED FOR INPUT OR OUTPUT (BDAM)
	.1. . . . . .		DCBOFLRB	"DCBBIT1"– LAST I/O OPERATION WAS IN READ BACKWARD MODE
	. .1. . . . .		DCBOFEOV	"DCBBIT2"– SET TO 1 BY EOV WHEN IT CALLS CLOSE ROUTINE FOR CONCATENATION OF DATA SETS WITH UNLIKE ATTRIBUTES
	. . .1 . . . .		DCBOFOPN	"DCBBIT3"– AN OPEN HAS BEEN SUCCESSFULLY COMPLETED
	. . . . 1. . .		DCBOFPPC	"DCBBIT4"– SET TO 1 BY PROBLEM PROGRAM TO INDICATE A CONCATENATION OF UNLIKE ATTRIBUTES
	. . . . .1. .		DCBOFTM	"DCBBIT5"– TAPE MARK HAS BEEN READ
	. . . . . .1.		DCBOFUEX	"DCBBIT6"– SET TO 0 BY AN I/O SUPPORT FUNCTION WHEN THAT FUNCTION TAKES A USER EXIT. SET TO 1 ON RETURN FROM USER EXIT TO THE I/O SUPPORT FUNCTION WHICH TOOK THE EXIT.
	. . . . . . .1		DCBOFIOF	"DCBBIT7"– SET TO 1 BY AN I/O SUPPORT FUNCTION IF DCB IS TO BE PROCESSED BY THAT FUNCTION
49 (31)	BITSTRING	1	DCBIFLG	– FLAGS USED BY IOS IN COMMUNICATING ERROR CONDITIONS AND IN DETERMINING CORRECTIVE PROCEDURES
	11. . . . . .		DCBIBEC	"DCBBIT0+DCBBIT1"– ERROR CORRECTION INDICATOR
	. . . . . . . .		DCBIFNEP	"X'00'"– NOT IN ERROR PROCEDURE
	.1. . . . . .		DCBEX	"DCBBIT1"– ERROR CORRECTION OR IOS PAGE FIX IN PROCESS
	11. . . . . .		DCBIFPEC	"DCBBIT0+DCBBIT1"– PERMANENT ERROR CORRECTION
	. .11 . . . .		DCBIBPCT	"DCBBIT2+DCBBIT3"– PRINTER CARRIAGE TAPE PUNCH INDICATOR
	. .1. . . . .		DCBIFC9	"DCBBIT2"– CHANNEL 9 PRINTER CARRIAGE TAPE PUNCH SENSED
	. . .1 . . . .		DCBIFC12	"DCBBIT3"– CHANNEL 12 PRINTER CARRIAGE TAPE PUNCH SENSED
	. . . . 11. .		DCBIBIOE	"DCBBIT4+DCBBIT5"– IOS ERROR ROUTINE USE INDICATOR
	. . . . . . . .		DCBIFER	"X'00'"– ALWAYS USE I/O SUPERVISOR ERROR ROUTINE
	. . . . .1. .		DCBIFNE1	"DCBBIT5"– NEVER USE I/O SUPERVISOR ERROR ROUTINE
	. . . . .1. .		DCBIFTIM	"DCBBIT5"– TEST IOS MASK (IMSK) FOR ERROR PROCEDURE (BTAM)
	. . . . 1. . .		DCBIFNE2	"DCBBIT4"– NEVER USE I/O SUPERVISOR ERROR ROUTINE
	. . . . 11. .		DCBIFNE3	"DCBBIT4+DCBBIT5"– NEVER USE I/O SUPERVISOR ERROR ROUTINE
50 (32)	BITSTRING	2	DCBMACR (0)	– MACRO INSTRUCTION REFERENCE
50 (32)	BITSTRING	1	DCBMACR1	– FIRST BYTE OF DCBMACR
	1. . . . . . .		DCBMRECP	"DCBBIT0"– EXECUTE CHANNEL PROGRAM (EXCP) --- ALWAYS ZERO (BSAM, QSAM, BPAM, BISAM, QISAM, BDAM) --- RESERVED (QTAM, BTAM)
	.1. . . . . .		DCBMRFE	"DCBBIT1"– FOUNDATION EXTENSION IS PRESENT (EXCP)
	.1. . . . . .		DCBMRGET	"DCBBIT1"– GET (QSAM, QISAM)
	.1. . . . . .		DCBMRPTQ	"DCBBIT1"– PUT FOR MESSAGE GROUP (QTAM) --- ALWAYS ZERO (BSAM, BPAM, BISAM, BDAM) --- RESERVED (BTAM)
	. .1. . . . .		DCBMRAPG	"DCBBIT2"– APPENDAGES ARE REQUIRED (EXCP)
	. .1. . . . .		DCBMRRD	"DCBBIT2"– READ (BSAM, BPAM, BISAM, BDAM, BTAM)
	. .1. . . . .		DCBMRWRQ	"DCBBIT2"– WRITE FOR LINE GROUP (QTAM) --- ALWAYS ZERO (QSAM, QISAM)
	. .1 . . . .		DCBMRCI	"DCBBIT3"– COMMON INTERFACE (EXCP)
	. . .1 . . . .		DCBMRMVG	"DCBBIT3"– MOVE MODE OF GET (QSAM, QISAM)
	. . .1 . . . .		DCBMRRDK	"DCBBIT3"– KEY SEGMENT WITH READ (BDAM) --- ALWAYS ZERO (BISAM) --- RESERVED (BSAM, BPAM, QTAM, BTAM)
	. . . . 1. . .		DCBMRLCG	"DCBBIT4"– LOCATE MODE OF GET (QSAM, QISAM)
	. . . . 1. . .		DCBMRRDI	"DCBBIT4"– ID ARGUMENT WITH READ (BDAM) --- ALWAYS ZERO (BISAM) --- RESERVED (EXCP, BSAM, BPAM, QTAM, BTAM)
	. . . . .1. .		DCBMRABC	"DCBBIT5"– USER'S PROGRAM MAINTAINS ACCURATE BLOCK COUNT (EXCP)
	. . . . .1. .		DCBMRPT1	"DCBBIT5"– POINT (WHICH IMPLIES NOTE) (BSAM, BPAM)
	. . . . .1. .		DCBMRSBG	"DCBBIT5"– SUBSTITUTE MODE OF GET (QSAM)
	. . . . .1. .		DCBMRDBF	"DCBBIT5"– DYNAMIC BUFFERING (BISAM, BDAM) --- ALWAYS ZERO (QISAM) --- RESERVED (QTAM, BTAM)
	. . . . . .1.		DCBPGFXA	"DCBBIT6"– PAGE FIX APPENDAGE IS SPECIFIED (EXCP)
	. . . . . .1.		DCBMRCRL	"DCBBIT6"– CNTRL (BSAM, QSAM)
	. . . . . .1.		DCBMRCHK	"DCBBIT6"– CHECK (BISAM)
	. . . . . .1.		DCBMRRDX	"DCBBIT6"– READ EXCLUSIVE (BDAM) --- RESERVED (BPAM, QISAM, QTAM, BTAM)
	. . . . . . .1		DCBMRDMG	"DCBBIT7"– DATA MODE OF GET (QSAM)
	. . . . . . .1		DCBMRCK	"DCBBIT7"– CHECK (BDAM) --- RESERVED (EXCP, BSAM, BPAM, BISAM, QISAM, QTAM, BTAM)
51 (33)	BITSTRING	1	DCBMACR2	– SECOND BYTE OF DCBMACR
	1. . . . . . .		DCBMRSTL	"DCBBIT0"– SETL (QISAM) --- ALWAYS ZERO (BSAM, QSAM, BPAM, BISAM, BDAM) --- RESERVED (EXCP, QTAM, BTAM)
	.1. . . . . .		DCBMRPUT	"DCBBIT1"– PUT (QSAM) – PUT OR PUTX (QISAM)
	.1. . . . . .		DCBMRGTQ	"DCBBIT1"– GET FOR MESSAGE GROUP (QTAM) --- ALWAYS ZERO (BSAM, BPAM, BISAM, BDAM) --- RESERVED (EXCP, BTAM)
	. .1. . . . .		DCBMRWRT	"DCBBIT2"– WRITE (BSAM, BPAM, BISAM, BDAM, BTAM)
	. .1. . . . .		DCBMRRDQ	"DCBBIT2"– READ FOR LINE GROUP (QTAM) --- ALWAYS ZERO (QSAM, QISAM) --- RESERVED (EXCP)
	. . .1 . . . .		DCBMRMVP	"DCBBIT3"– MOVE MODE OF PUT (QSAM, QISAM)
	. . .1 . . . .		DCBMRWRK	"DCBBIT3"– KEY SEGMENT WITH WRITE (BDAM) --- ALWAYS ZERO (BISAM) --- RESERVED (EXCP, BSAM, BPAM, QTAM, BTAM)
	. . . . 1. . .		DCBMR5WD	"DCBBIT4"– FIVE-WORD DEVICE INTERFACE (EXCP)
	. . . . 1. . .		DCBMRLDM	"DCBBIT4"– LOAD MODE BSAM (CREATE BDAM DATA SET) (BSAM)
	. . . . 1. . .		DCBMRLCP	"DCBBIT4"– LOCATE MODE OF PUT (QSAM, QISAM)
	. . . . 1. . .		DCBMRIDW	"DCBBIT4"– ID ARGUMENT WITH WRITE (BDAM) --- ALWAYS ZERO (BISAM) --- RESERVED (BPAM, QTAM, BTAM)
	. . . . .1. .		DCBMR4WD	"DCBBIT5"– FOUR–WORD DEVICE INTERFACE (EXCP)
	. . . . .1. .		DCBMRPT2	"DCBBIT5"– POINT (WHICH IMPLIES NOTE) (BSAM, BPAM)
	. . . . .1. .		DCBMRTMD	"DCBBIT5"– SUBSTITUTE MODE (QSAM)
	. . . . .1. .		DCBMRUIP	"DCBBIT5"– UPDATE IN PLACE (PUTX) (QISAM) --- ALWAYS ZERO (BISAM) --- RESERVED (BDAM, QTAM, BTAM)
	. . . . . .1.		DCBMR3WD	"DCBBIT6"– THREE–WORD DEVICE INTERFACE (EXCP)
	. . . . . .1.		DCBMRCTL	"DCBBIT6"– CNTRL (BSAM, QSAM)
	. . . . . .1.		DCBMRSTK	"DCBBIT6"– SETL BY KEY (QISAM)
	. . . . . .1.		DCBMRAWR	"DCBBIT6"– ADD TYPE OF WRITE (BDAM) --- ALWAYS ZERO (BISAM) --- RESERVED (BPAM, QTAM, BTAM)
	. . . . . . .1		DCBMR1WD	"DCBBIT7"– ONE–WORD DEVICE INTERFACE (EXCP)
	. . . . . . .1		DCBMRSWA	"DCBBIT7"– USER'S PROGRAM HAS PROVIDED A SEGMENT WORK AREA POOL (BSAM CREATE BDAM, BDAM)
	. . . . . . .1		DCBMRDMD	"DCBBIT7"- DATA MODE (QSAM)
	. . . . . . .1		DCBMRSTI	"DCBBIT7"– SETL BY ID (QISAM) — ALWAYS ZERO (BISAM) — RESERVED (BPAM, QTAM, BTAM)
FOUNDATION AFTER OPEN
40 (28)	ADDRESS	2	DCBTIOT	OFFSET FROM TIOT ORIGIN TO TIOELNGH FIELD IN TIOT ENTRY FOR DD STATEMENT ASSOCIATED WITH THIS DCB
42 (2A)	BITSTRING	2	DCBMACRF (0)	– SAME AS DCBMACR BEFORE OPEN
42 (2A)	BITSTRING	1	DCBMACF1	– FIRST BYTE OF DCBMACRF
43 (2B)	BITSTRING	1	DCBMACF2	– SECOND BYTE OF DCBMACRF
44 (2C)	ADDRESS	4	DCBDEBAD (0)	– ADDRESS OF ASSOCIATED DEB
44 (2C)	BITSTRING	1	DCBIFLGS	– SAME AS DCBIFLG BEFORE OPEN
	11. . . . . .		DCBIFEC	"DCBBIT0+DCBBIT1"– ERROR CORRECTION INDICATOR
	. .11 . . . .		DCBIFPCT	"DCBBIT2+DCBBIT3"– PRINTER CARRIAGE TAPE PUNCH INDICATOR
	. . . . 11. .		DCBIFIOE	"DCBBIT4+DCBBIT5"– RROR ROUTINE USE INDICATOR
	. . . . . .1.		DCBIFLDT	"DCBBIT6"– POSSIBLE LOST DATA CONDITION SUCH AS FOR A PRINTER
45 (2D)	ADDRESS	3	DCBDEBA	– ADDRESS OF ASSOCIATED DEB
48 (30)	ADDRESS	4	DCBREAD (0)	– ADDRESS OF READ MODULE
48 (30)	ADDRESS	4	DCBWRITE (0)	– ADDRESS OF WRITE MODULE
48 (30)	BITSTRING	1	DCBOFLG	SAME AS DCBOFLGS BEFORE OPEN
49 (31)	ADDRESS	3	DCBREADA (0)	ADDRESS OF READ MODULE
49 (31)	ADDRESS	3	DCBWRITA	ADDRESS OF WRITE MODULE
BDAM INTERFACE
52 (34)	ADDRESS	4	DCBCHECK (0)	– ADDRESS OF CHECK MODULE
52 (34)	BITSTRING	1	DCBOPTCD	– OPTION CODES
	1. . . . . . .		DCBOPTW	"DCBBIT0"– WRITE VALIDITY CHECK (DASD) (BSAM, BPAM, QSAM, ISAM, BDAM)
	.1. . . . . .		DCBOPTTO	"DCBBIT1"– TRACK OVERFLOW
	. .1. . . . .		DCBOPTE	"DCBBIT2"– EXTENDED SEARCH
	. . .1 . . . .		DCBOPTF	"DCBBIT3"– FEEDBACK
	. . . . 1. . .		DCBOPTA	"DCBBIT4"– ACTUAL ADDRESSING
	. . . . .1. .		DCBOPTDB	"DCBBIT5"– DYNAMIC BUFFERING
	. . . . . .1.		DCBOPTRE	"DCBBIT6"– READ EXCLUSIVE
	. . . . . . .1		DCBOPTRB	"DCBBIT7"– RELATIVE BLOCK ADDRESSING
53 (35)	ADDRESS	3	DCBCHCKA	– ADDRESS OF CHECK MODULE
56 (38)	ADDRESS	4	DCBSYNAD	– ADDRESS OF SYNAD ROUTINE
60 (3C)	BITSTRING	2		– RESERVED
62 (3E)	SIGNED	2	DCBBLKSI	– MAXIMUM BLOCK SIZE
64 (40)	ADDRESS	4	DCBIOBSQ	– ADDRESS OF FIRST IOB ON UNSCHEDULED QUEUE FOR EITHER A WRITE–ADD REQUEST WHEN ANOTHER WRITE– ADD IS IN PROGRESS OR A READ–EXCLUSIVE REQUEST WHEN THE READ–EXCLUSIVE LIST IS FULL
68 (44)	ADDRESS	4	DCBSQND	– ADDRESS OF LAST IOB ON UNSCHEDULED QUEUE
72 (48)	ADDRESS	4	DCBIOBUQ	– ADDRESS OF FIRST IOB ON UNPOSTED QUEUE
76 (4C)	ADDRESS	4	DCBUQND	– ADDRESS OF LAST IOB ON UNPOSTED QUEUE THAT IS MAINTAINED BY THE READ EXCLUSIVE MODULE
80 (50)	BITSTRING	1		– RESERVED
81 (51)	SIGNED	3	DCBLIMCT	– NUMBER OF TRACKS OR NUMBER OF RELATIVE BLOCKS TO BE SEARCHED (EXTENDED SEARCH OPTION)
84 (54)	ADDRESS	4	DCBXARG (0)	– ADDRESS OF READ EXCLUSIVE LIST
84 (54)	SIGNED	1	DCBXCNT	– NUMBER OF ENTRIES IN READ EXCLUSIVE LIST
85 (55)	ADDRESS	3	DCBXARGA	– ADDRESS OF READ EXCLUSIVE LIST
88 (58)	ADDRESS	4	DCBDRDX (0)	– ADDRESS OF READ EXCLUSIVE MODULE
88 (58)	SIGNED	1	DCBMVXNO	– TOTAL NUMBER OF EXTENTS IN MULTIVOLUME DATA SET
89 (59)	ADDRESS	3	DCBDRDXA	– ADDRESS OF READ EXCLUSIVE MODULE
92 (5C)	ADDRESS	4	DCBDFOR	– ADDRESS OF A FORMAT MODULE
96 (60)	ADDRESS	4	DCBDFBK	– ADDRESS OF A FEEDBACK MODULE
100 (64)	ADDRESS	4	DCBDYNB	– FOR DYNAMIC BUFFERING, ADDRESS OF DYNAMIC BUFFER MODULE. FOR UNBLOCKED SPANNED RECORDS WITH BFTEK=R SPECIFIED AND NO DYNAMIC BUFFERING, ADDRESS OF SEGMENT WORK AREA CONTROL BLOCK