Offset | Type/Value | Len | Name (Dim) | Description |
---|---|---|---|---|
DATA CONTROL BLOCK DEFINITION |
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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" | ||
GRAPHIC DEVICE INTERFACE |
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0 (0) | BITSTRING | 12 | – RESERVED | |
12 (C) | ADDRESS | 2 | DCBBRSA | – BUFFER RESTART ADDRESS. BLANK BEFORE EXECUTION OF SECOND I/O OPERATION |
14 (E) | CHARACTER | 1 | DCBGTYPE | – TYPE OF BUFFER MANAGEMENT AND ATTENTION HANDLING |
. . . . . . . . | DCBGTEXP | "X'00'"– EXPRESS | ||
. . . . . . .1 | DCBGTBAS | "X'01'"– BASIC | ||
. . . . . .1. | DCBGTNBM | "X'02'"– DEFAULT – NO BUFFER MANAGEMENT | ||
15 (F) | BITSTRING | 1 | – RESERVED | |
16 (10) | ADDRESS | 2 | DCBBFRST | – BLANK BEFORE EXECUTION OF OPEN ROUTINE. STARTING ADDRESS FOR BUFFER AFTER EXECUTION OF OPEN ROUTINE |
18 (12) | SIGNED | 2 | DCBBFRSZ | – BLANK BEFORE EXECUTION OF OPEN ROUTINE. SIZE OF BUFFER AFTER EXECUTION OF OPEN ROUTINE. |
COMMON INTERFACE |
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20 (14) | BITSTRING | 6 | – RESERVED | |
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 | – SECOND 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 | – BLANK BEFORE EXECUTION OF OPEN ROUTINE. ADDRESS OF STANDARD FIELDS OF FIRST IOB AFTER EXECUTION OF OPEN ROUTINE |
FOUNDATION EXTENSION |
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32 (20) | ADDRESS | 4 | DCBPOLST (0) | – ADDRESS OF AREA WHERE A DCB LIST IS TO BE CONSTRUCTED FOR POLLING PURPOSES |
32 (20) | SIGNED | 1 | DCBGNCP | – NUMBER OF I/O INSTRUCTIONS TO BE ISSUED BEFORE A WAIT MACRO INSTRUCTION |
33 (21) | ADDRESS | 3 | DCBPOLSA | – SAME AS DCBPOLST ABOVE |
36 (24) | ADDRESS | 4 | DCBEXLST (0) | – ADDRESS OF USER'S EXIT LIST |
36 (24) | BITSTRING | 1 | – RESERVED | |
37 (25) | ADDRESS | 3 | DCBEXLSA | – ADDRESS OF USER'S EXIT LIST |
FOUNDATION BEFORE OPEN |
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40 (28) | CHARACTER | 8 | DCBDDNAM | – 8–BYTE NAME FROM DD STATEMENT THAT DEFINES DATA SET ASSOCIATED WITH THIS DCB |
48 (30) | BITSTRING | 1 | DCBOFLG | – FLAGS USED BY OPEN ROUTINE |
1. . . . . . . | DCBOFGRW | "DCBBIT0"– IF ZERO, LAST I/O OPERATION WAS GREAD. IF ONE, LAST I/O OPERATION WAS GWRITE. | ||
1 | . .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 | . . . . 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 | . . . . . .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 | – SET TO ZERO BY GRAPHIC ROUTINES BUT USED BY IOS IN COMMUNICATING ERROR CONDITIONS AND IN DETERMINING CORRECTIVE PROCEDURES |
50 (32) | BITSTRING | 2 | DCBMACR (0) | – MACRO INSTRUCTION REFERENCE |
50 (32) | BITSTRING | 1 | DCBMACR1 | – FIRST BYTE OF DCBMACR |
. .1. . . . . | DCBMRRD | "DCBBIT2"– READ | ||
. . . . . .1. | DCBMRCRL | "DCBBIT6"– CNTRL | ||
51 (33) | BITSTRING | 1 | DCBMACR2 | – SECOND BYTE OF DCBMACR |
. .1. . . . . | DCBMRWRT | "DCBBIT2"– WRITE | ||
. . . . . .1. | DCBMRCTL | "DCBBIT6"– CNTRL | ||
FOUNDATION AFTER OPEN |
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40 (28) | ADDRESS | 2 | DCBTIOT | – OFFSET FROM TIOT ORIGIN TO DD ENTRY 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 |
45 (2D) | ADDRESS | 3 | DCBDEBA | – ADDRESS OF ASSOCIATED DEB |
48 (30) | ADDRESS | 4 | DCBGIOCR (0) | – ADDRESS OF GRAPHICS I/O CONTROL ROUTINE |
48 (30) | BITSTRING | 1 | DCBOFLGS | – SAME AS DCBOFLG BEFORE OPEN |
49 (31) | ADDRESS | 3 | DCBGIOCA | – ADDRESS OF GRAPHICS I/O CONTROL ROUTINE |