Data Facilities Area (DFA) Fields

Except for DFADFVAD, all of the fields in the DFA are part of the intended programming interface.

Common Name:
Data Facilities Area
Macro ID:
IHADFA
DSECT Name:
DFA
Eye-Catcher ID:
DFAACRON
Subpool and Key:
Nucleus resident and Key 0; Resident below 16MB
Size:
112 bytes
Created by:
Assembled into nucleus
Pointed to by:
CVTDFA field of the CVT
Serialization:
N/A
Function:
Maps the Data Facilities Area, which contains information that applies to DFSMS.
Table 1. DFA Fields
Offset   Type/Value Length Name Description
0(0)   UNSIGNED 2 DFALEN LENGTH OF THIS TABLE  
Version, release, and modification level information for DFP. The first three digits of DFAREL represents the last level of DFP(X'332'). The fourth digit of DFAREL being nonzero indicates the level of THIS product is later than the indicated level.
2(2)   BITSTRING 2 DFAREL FOUR DIGITS = VERSION, RELEASE, MOD, X  
The following are the feature bytes. When a bit is on, it means either that the current release supports the feature or that this particular instance of the system supports the feature. If the software supports a feature but it cannot be used, perhaps because corequisite software or hardware is not available, then the feature bit will be off.
4(4)   SIGNED 4 DFAFEATS(0) ALL FEATURES BYTES–USED BY CS INSTR
4(4)   BITSTRING 1 DFAFEAT1 FEATURES BYTE 1
    1... ....   DFAXA "X'80'" MVS/XA (COPY OF CVTMVSE IN CVT)
    .1.. ....   DFALSR Multiple VSAM LSR pools supported (MVS/XA DFP 1.1.0 in 1983)
    ..1. ....   DFAEOS DASDM erase on scratch supported (MVS/XA DFP 2.1.0 in 1985)
    ...1 ....   DFAXRF Extended recovery facility (MVS/XA DFP 2.1.0)
    .... 1...   DFAEXPCI EXPORT by control interval (MVS/XA DFP 2.1.0)
    .... .1..   DFAEOSIC ERASE on scratch for ICF (MVS/XA DFP 2.1.0)
    .... ..1.   DFASMS System managed storage (SMS) (MVS/DFP 3.1.0 in 1989)
Start of change End of change Start of change End of change Start of change.... ...1End of change Start of change End of change Start of changeDFAPDSEEnd of change Start of change"X'01'" PDSE SUPPORT AVAILABLE ON THE SYSTEM SET WHEN DFP LEVEL IS 3.2.0 OR GREATER AND AN APPROPRIATE LEVEL OF SP EXISTS.End of change
    .... ...1   DFAIPDS "DFAPDSE" IPDS IS OLD NAME FOR PDSE
5(5)   BITSTRING 1 DFAFEAT2 FEATURES BYTE 2
    1... ....   DFADLS "X'80'" RESERVED
    .1.. ....   DFAPML "X'40'" RESERVED
    ..1. ....   DFAFMS "X'20'" FILE MANAGEMENT SERVICES SUPPORTED
    ...1 ....   DFACMPAC "X'10'" INSTALLATION DEFAULT FOR COMPACTION
    .... 1...   DFABPBLD "X'08'" BYPASS CHANNEL PROGRAM PREFIX BUILD
    .... .1..   DFASSF "X'04'" SSF SERVICES ARE AVAILABLE
    .... ..1.   DFAMMEXT "X'02'" MMS SUPPORTS XTIOT
    .... ...1   DFAINDEF "X'01'" COMPACTION DEFAULT EXPLICITLY SET BY INSTALLATION
6(6)   BITSTRING 1 DFAFEAT3 FEATURES BYTE 3
    1... ....   DFAVOLSN "X'80'" VOLSER EXTRACTED FROM SENSE INFO ACCEPTABLE BY THE INSTALLATION
    .1.. ....   DFASAMEX EXTENDED FORMAT SEQUENTIAL DATA SETS SUPPORTED
    .1.. ....   DFASMSEX ALIAS FOR DFASAMEX
    ..1. ....   DFAKSDEX EXTENDED FORMAT KSDS SUPPORTED
    ...1 ....   DFACMPCT DFSMS ACCESS METHOD COMPRESSION SUPPORTED. BIT SET BY SMS SUB-SYSTEM INITIALIZATION.
    .... 1...   DFARLSJ3 THE SMSVSAM SERVER HAS SUCCESSFULLY INITIALIZED ON THIS SYSTEM. THIS BIT IS USED BY SMS SCHEDULING. ONCE ON, THIS BIT REMAINS ON FOR THE LIFE OF THE IPL. THIS BIT DOES NOT INDICATE THAT THE SMSVSAM SERVER IS CURRENTLY OPERATIONAL.
    .... .1..   DFARECAL DATA SET RECALL CAPABILITY VIA® THE ARCHRCAL MACRO IS AVAILABLE.
    .... ..1.   DFADEEXT DESERV EXIT FUNCTION IS AVAILABLE
    .... ...1   DFADLL DFSMS DLL SUPPORT IS AVAILABLE
7(7)   BITSTRING 1 DFAFEAT4 FEATURES BYTE 4
    1... ....   DFAFDAT RESERVED
    .1.. ....   DFANSRV DFP NIP SERVICES CAN BE INVOKED VIA IGGSSRV MACRO
    ..1. ....   DFADYNL DYNAMIC LINKLIST IS SUPPORTED
    ..1. ....   DFACIR2 THE CATALOG INFORMATION ROUTINE, IKJEHCIR, SUPPORTS A FORMAT 2 WORK AREA, I.E., FULL WORD LENGTH FIELDS
    .... 1...   DFADYLPA DFSMS SUPPORT FOR DYNAMIC LPA IS AVAILABLE.
    .... .1..   DFAFORK DFSMS LOADER FORK EXIT IS PRESENT
    .... ..1.   DFASNBK SOFTWARE SUPPORT PROVIDING “FAST” BACKUP USING THE SNAPSHOT FEATURE OF THE RAMAC VIRTUAL ARRAY (RVA) INSTALLED.
    .... ...1   DFASNAP THE API SUPPORT FOR THE SNAPSHOT FEATURE OF THE RAMAC VIRTUAL ARAY (RVA) IS INSTALLED.
8(8)   CHARACTER 4 DFAACRON ACRONYM FOR THIS CONTROL BLOCK.
12(C)   BITSTRING 1 DFAFEAT5 FEATURES BYTE 5
    1... ....   DFAUPDSE UNMANAGED PDSE SUPPORT INSTALLED ON THIS SYSTEM.
    .1.. ....   DFABTSREQ 1 means BLOCKTOKENSIZE=REQUIRE in IGDSMSxx member of PARMLIB. Restrictions on opening large format data sets. 0 means BLOCKTOKENSIZE=NOREQUIRE.
    ..1. ....   DFABLDLS BLDL START= and STOP= parameters are supported.
    ...1 ....   DFAUSEAV System default USEEAV setting for an extended address volume (EAV) when SMS is not active. Initially set on, to allow the use of EAV, and changed to the IGDSMSxx PARMLIB specified or defaulted USEEAV value if SMS is active.
    ....1...   DFASAMHPF SAM_USE_HPF, On = yes

Note: If DFASAMHPF is set but ZHPF=YES in IECIOSxx is not in effect, BAM will not use zHPF.
    ..... .1..     USS PIPES LBI support
    .... ..1.   DFAALVER VERSION LEVEL AT WHICH NEW TAPE LABELS WILL BE WRITTEN. OFF: ANSI LABEL VERSION 3. ON: ANSI LABEL VERSION 4.
    .... ...1   DFAALFOR DETERMINES WHETHER INSTALLATION ISO/ANSI VERSION LEVEL IS FORCED
13(D)   BITSTRING 1 DFAFEAT6 FEATURES BYTE 6
    1111 ....   DFACPSDB COPYSDB VALUE IN DEVSUPxx IN PARMLIB. SYSTEM LEVEL DEFAULT FOR THE SDB OPTION OF IEBGENER AND OTHER COPYING PROGRAMS. VAE CONSTANTS BELOW DFACPS**
    0001 ....   DFACPSNO COPYSDB = NO
    0010 ....   DFACPSYE COPYSDB = YES
    0010 ....   DFACPSSM COPYSDB = SMALL (SAME AS COPYSDB = YES)
    0011 ....   DFACPSIN COPYSDB = INPUT
    0100 ....   DFACPSLA COPYSDB = LARGE
    .... 1...   DFADCMET Data class media enforced for all tapes outside of libraries (ENFORCE_DC_MEDIA=ALMEDIATY)
    .... .1..   DFADCMEJ Data class media enforced for IBM® 3592 outside of libraries (ENFORCE_DC_MEDIA=MEDIA5PLUS)
    .... ..1.   DFAMTLAM When no media preference is expressed, accept all media types for a manual tape library (MTL_NO_DC_WORM_OK)
    .... ...1   DFASTIFF STOW supports the IFF operand
14(E)   UNSIGNED 2 DFABPV System default break point value (BPV) for an extended address volume (EAV) when the BPV is not specified in the SMS IGDSMSxx PARMLIB or when SMS is not active. Initially set to 10 and changed to the IGDSMSxx SPECIFIED BPV value if SMS is active.
PRODUCT, VERSION, RELEASE, AND MODIFICATION LEVEL INFORMATION. BYTE 0 DEFINES A PRODUCT CODE, BYTES 1-3 DEFINE THE VERSION, RELEASE, AND MODIFICATION LEVELS OF THIS PRODUCT. A PRODUCT BYTE (DFAPROD) OF X'00' INDICATES DFP AS A PRODUCT, BYTES 1-3 OF DFARELS WILL ALSO BE X'00' IN THIS CASE. THE USER MAY CHOOSE TO CHECK DFAREL FOR THE RELEASE LEVEL OF THE DFP PRODUCT IN THIS CASE. IF DFAPROD IS NOT EQUAL TO X'00', DFAREL SHOULD NOT BE CHECKED AS IT WILL BE FROZEN AT THE LAST LEVEL OF DFP PRODUCT SHIPPED. A PRODUCT BYTE (DFAPROD) OF X'01' INDICATES DFSMS AS A PRODUCT BYTES 1-3 OF DFARELS WILL INDICATE THE VERSION, RELEASE AND MODIFICATION LEVELS OF THE DFSMS PRODUCT. A PRODUCT BYTE (DFAPROD) OF X'02' INDICATES OS/390®. THIS VALUE INDICATES THIS LEVEL OF DFSMS IS OS/390 EXCLUSIVE. SINCE DFSMS MIGHT NOT BE REFRESHED WITH EACH OS/390 RELEASE, THE VERSION, RELEASE, AND MODIFICATION FIELDS INDICATE THE LEVEL OF OS/390 IN WHICH THIS LEVEL OF DFSMS WAS FIRST SHIPPED. THE VERSION, RELEASE, AND MODIFICATION FIELDS ARE BINARY VALUES. (FOR EXAMPLE TEN WOULD BE X'0A').
16(10)   BITSTRING 4 DFARELS 4 BYTES = PRODUCT, VERSION, REL, MOD
16(10)   BITSTRING 1 DFAPROD PRODUCT BYTE
    0000 0000   DFADFP DFP PRODUCT CODE.
    0000 0001   DFADFSMS PRODUCT CODE FOR DFSMS.
    0000 0002   DFAOS390 PRODUCT CODE FOR OS/390 VERSION 2.
    0000 0003   DFAZOS PRODUCT CODE FOR z/OS®.
17(11)   BITSTRING 1 DFAVER VERSION BYTE
18(12)   BITSTRING 1 DFARLSE RELEASE BYTE
19(13)   BITSTRING 1 DFAMOD MODIFICATION BYTE
20(14)   SIGNED 2 DFAMSMDE MAXIMUM LENGTH OF THE SMDE IN THIS RELEASE WITH AN 8-BYTE ALIAS NAME
22(16)   UNSIGNED 1 DFAVERBO FLAGS
    1... ....   DFAMTPPRC Multi-Target PPRC
    .1.. ....   DFATVS tvs flag
    ..1. ....   DFAFCXHS FlashCopy® across Hyperswap enabled
    ...1 ....   DFASYMCF Reserved: PPRC symmetrical configuration
    .... 1...   DFAREJDEVGRP SIO Exit Reject IO if
    .... .1..   DFAINCFC Multiple Incremental FlashCopy
    .... ..11   * Reserved
23(17)   UNSIGNED 1 DFASEFVR Data set format version for new sequential extended format data sets. This is set by the PS_EXT_VERSION keyword in the IGDSMSxx member of SYS1.PARMLIB.
24(18)   ADDRESS 4 DFACSSVT CALLABLE SYSTEM SERVICES VECTOR TABLE ADDRESS
28(1C)   ADDRESS 4 DFADCVSO DATA CONVERSION SERVICES –OPEN.
32(20)   ADDRESS 4 DFADCVSD DATA CONVERSION SERVICES –CONVERT.
36(24)   ADDRESS 4 DFADCVSC DATA CONVERSION SERVICES –CLOSE.
40(28)   ADDRESS 4 DFAELNMP Address of DFSMS element name. Name is mapped by DSECT DFAELNM. See Table 2. Valid only on z/OS 1.3 and later.
44(2C)   ADDRESS 4 DFADFVAD DATA FACILITIES VECTOR TABLE ADDR
End of DFA as it was when it was first shipped in MVS/XA DFP Version 2 Release 1 Modification Level 0. Prior to referencing any field beyond this comment, the user must ensure that DFARELS is greater than or equal to X'02020A00' or DFALEN is big enough. (See DFALEN.)
48(30)   INTEGER 8 DFABLKSZ LIMIT ON SYSTEM DETERMINED BLOCK SIZE. DEFAULT IS 32760. OBTAINED FROM DEVSUPxx PARMLIB MEMBER.
56(38)   BITSTRING 1 DFAFEAT7 FEATURES BYTE 7 
    1... ....   DFATADSN TAPEAUTHDSN=YES
    .1.. ....   DFATADS1 TAPEAUTHF1=YES
    ..1. ....   DFATARC8 TAPEAUTHRC8=WARN
    ...1 ....   DFATARC4 TAPEAUTHRC4=FAIL
    .... 1...   DFAXTBAM THE NON_VSAM_XTIOT OPTION OF THE DEVSUPxx MEMBER OF PARMLIB HAS BEEN SET TO 'YES'.
    .... .1..   DFATPMVA TAPEMULTIVOLUMEERROR=ALLOW.
    .... ..1.   DFATPMVF TAPEMULTIVOLUMEERROR=FAIL.
    .... ...1   DFA253 SUBSYSTEMS SUPPORTED
57(39)   BITSTRING 1 DFAFEAT8 FEATURES BYTE 8. The following 7 flags indicate VSAM and non-VSAM data set support for the Extended Addressing Space (EAS) on an EAV.
THE FOLLOWING 8 FLAGS INDICATE VSAM AND NON-VSAM DATA SET SUPPORT FOR THE EXTENDED ADDRESSING SPACE (EAS) ON AN EAV
    1... ....   DFAVSAMFOREAS VSAM enabled for EAS
    .1.. ....   DFASEQFOREAS Basic, large format sequential (QSAM, BSAM, BDAM access) enabled for EAS
    ..1. ....   DFAPDSEFOREAS PDSE enabled for EAS
    ...1 ....   DFAPDSFOREAS PDS enabled for EAS
    .... 1...   DFADIRFOREAS Direct (BDAM access) enabled for EAS
    .... .1..   DFAEFSEQFOREAS Extended format sequential enabled for EAS
    .... ..1.   DFAUNDEFFOREAS Undef DSORGs enabled for EAS
    .... ...1   DFAEXPMSG EXPIRATION_MESSAGE=NEVER
58(3A)   Unsigned 2 DFADDRSZ Storage size limit allowed in DDR swap (number of megabytes)
60 (3C)   Bit string 1 DFAFEAT9 Features byte 9
  1... .... DFAJ3AA JES3_ALLOC_ASSIST=YES in DEVSUPxx
  .1.. .... DFAMEMUX This level of the system supports IEBCOPY member selection user exits
    ..1. ....   DFAPDSEG PDSE Generation support is installed
    ...1 ....   DFAZEDCCMP zEDC Compression support is installed
Start of changeEnd of change   …. 1...   DFASSREN DADSM extend secondary space reduction enabled
Start of changeEnd of change   …. .1..   DFASYSZADRV DSS full volume dump and restore obtains SYSZADRV/volser/SYSTEMS resource to avoid lockout
  .... ..1. DFABYPAUTH DCBE Bypass Authorization support is installed
    .... ...1   DFAENCRYPT DFSMS support for Data Set Encryption is installed
61 (3D)   CHARACTER 1 Reserved
61 (3D)   3 Reserved
Start of change61 (3E)End of change Start of change End of change Start of changeBit stringEnd of change Start of change1End of change Start of changeDFADEVX1End of change Start of changeDEVSUPXX PARMLIB FLAG-1End of change
Start of change End of change Start of change1... ....End of change Start of change End of change Start of changeDFAEOSV2End of change Start of changeErase-On-Scratch PPRC Version 2End of change
Start of change End of change Start of change.1.. ....End of change Start of change End of change Start of changeDFADDSFVOFFEnd of change Start of changeICKDSF VERIFY OFFLINE supportEnd of change
Start of change End of change Start of change..1. ....End of change Start of change End of change Start of changeDFADSFNODSEnd of change Start of changeDSF NODSEXIST statusEnd of change
Start of change End of change Start of change...1 ....End of change Start of change End of change Start of changeDFAREFUCBFAEnd of change Start of changeREFUCB Failure ActionEnd of change
Start of change End of change Start of change.... 1...End of change Start of change End of change Start of changeDFAVTOCZHPFEnd of change Start of changeVTOC_USE_ZHPF keywordEnd of change
Start of change End of change Start of change.... .1..End of change Start of change End of change Start of changeDFATCTCOMPEnd of change Start of changeTCTCOMPRESSION keywordEnd of change
62 (3E)   Bit string 1 DFADEVX1 DEVSUPXX PARMLIB FLAG-1
    1... ....   DFAEOSV2 ERASE-ON-SCRATCH VERSION 2
    .1.. ....   DFADDSFVOFF Disable ICKDSF VERIFYOFFLINE
Start of change End of change Start of change End of change Start of change..1. .... End of change Start of change End of change Start of changeDFADSFNODS End of change Start of changeICKDSF NODSEXIST status flagEnd of change
Start of change End of change Start of change End of change Start of change...1 .... End of change Start of change End of change Start of changeDFAREFUCBFAEnd of change Start of changeREFUCB Failure action flagEnd of change
63 (3F)   Bit string 1 DFADEVX2 DEVSUPXX PARMLIB FLAG-2
Start of change64 (40)End of change     8   Reserved
72 (48)   Bit string 4 DFAFEATC HPF/FCX Feature Code bytes
Start of change72 (48) End of change   Bit string 1 DFAHPFC1 HPF Features
  .... 1... DFAFCX_TTEDcw Transfer TCA Extension
  .... .1.. DFAFCX_REL1 FCX phase 1
  .... ..1. DFAFCX_ImbeddedLR Imbedded LR List
  .... ...1 DFAFCX_FmtUpdWrt Format Update Writes
73 (49)   Bit string 1 Second HPF feature code byte
  1... .... DFAFCX_FmtWrite Format Write Enable
74 (4A)   Bit string 1   Third HPF feature code byte
75 (4B)   Bit string 1   Fourth HPF feature code byte
76 (4C)   Unsigned 4 DFAMAXGN Maximum number of generations allowed in a PDSE
80 (50)   Unsigned 1 DFACMPTYPE Default compression type
        DFACMPTYPEGEN 0 = Generic compression
        DFACMPTYPETLRD 1 = Tailored compression
        DFACMPTYPEzEDCR 2 = zEDC compression required
        DFACMPTYPEzEDCP 3 = zEDC compression preferred
81 (51)   Bit string 1 DFAFEAT10 Features byte 10
    ...1 ....   DFADEBLock DEBCHK Lock function support
  1... .... DFAROSEC Read-Only Secondary support is installed on the system
Start of changeEnd of change   .1.. ….   DFADSSBAbove DSSB Above the Bar for data sets accessed with VSAM or MMSRV
    ..1. ....   DFADEVTYPEXTIOT DEVTYPE XTIOT=YES/NO support
    ...1 ….   DFADEBLock DEBCHK lock function support
Start of changeEnd of change   …. 1...   DFASyncIoWrites zHyperLink (SyncIO) Write support installed
    …. .1..   DFAPDSEGENCPY PDSE Generation Copy Support
    …. ..1.   DFAPDSEENCRYPT PDSE Encryption support
Start of change82 (52)End of change Start of change End of change Start of changeBit stringEnd of change Start of change1End of change Start of changeDFAFEAT11End of change Start of changeFeatures byte 11End of change
    1... ....   DFASEQENCRYPT Start of changeBasic and large format data set encryption support installed and initialized.End of change
Start of change End of change Start of change End of change Start of change.1.. ....End of change Start of change End of change Start of changeDFACATALOGINFOVALID End of change Start of changeCatalog fields DFACATINFO and DFACatAliasLvl below are valid.End of change
Start of change End of change Start of change End of change Start of change..1. ….End of change Start of change End of change Start of changeDFAMMDUALLOGEnd of change Start of changeMedia Manager Dual Log SupportEnd of change
Start of changeEnd of change   ...1 1111   Reserved
Start of change83 (53)End of change Start of change End of change Start of changeBit string End of change Start of change1End of change Start of changeDFACATINFO End of change Start of changeCatalog information. These fields are provided for programs that need information about Catalog functions.End of change
Start of change End of change Start of change End of change Start of change1... .... End of change Start of change End of change Start of changeDFACatGDGExt End of change Start of changeGDG Extended enabledEnd of change
Start of change End of change Start of change End of change Start of change.1.. .... End of change Start of change End of change Start of changeDFACatGDGFIFO End of change Start of changeGDG FIFO enabledEnd of change
Start of change End of change Start of change End of change Start of change..1. .... End of change Start of change End of change Start of change DFACatGDGScrDEnd of change Start of changeGDG Scratch Default enabledEnd of change
Start of change End of change Start of change End of change Start of change ...1 ....End of change Start of change End of change Start of changeDFACatGDGPrgD End of change Start of changeGDG Purge Default enabledEnd of change
Start of change End of change Start of change End of change Start of change .... 1...End of change Start of change End of change Start of changeDFACatSYSPer End of change Start of changeCatalog SYSPERCENT enabledEnd of change
Start of change End of change Start of change End of change Start of change.... .111 End of change Start of change End of change Start of changeReservedEnd of change Start of change End of change
Start of change84(54) End of change Start of change End of change Start of changeUnsignedEnd of change Start of change 1End of change Start of changeDFACatAliasLvl End of change Start of changeCatalog Alias levels numberEnd of change
Start of change85(55)End of change Start of change End of change Start of change End of change Start of change 27End of change Start of change End of change Start of changeReservedEnd of change
Table 2. DFA Element Name
Offset Type/Value Length Name Description
0(0) DSECT   DFAELNM DSECT name
0(0) UNSIGNED 2 DFAELNML Length of significant characters in next field. Currently ten.
2(2) CHARACTER 22 DFAEXTXT DFSMS element name in EBCDIC. May contain lowercase characters. Currently is "z/OS DFSMS".