Subparameter definition

AMORG

Indicates that the DD statement describes a VSAM data set. Code AMORG when data set access is through an ISAM interface program and the DD statement contains VOLUME and UNIT parameters.

It is unnecessary to code AMP=AMORG for a data set that is SMS-managed. An SMS data set is cataloged at allocation; all information pertaining to the data set creation (such as RECORG) must be fully defined at allocation to ensure the success of the job.

BUFND=number

Specifies the number of I/O buffers that VSAM is to use for data records. The minimum is 1 plus the STRNO subparameter number. This value overrides the BUFND value specified in the ACB or GENCB macro, or provides a value if one is not specified. If you omit STRNO, BUFND must be at least 2.

If you omit BUFND from AMP and from the ACB macro instruction, the system uses the STRNO number plus 1.

BUFNI=number

Specifies the number of I/O buffers that VSAM is to use for index records. This value overrides the BUFNI value specified in the ACB or GENCB macro, or provides a value if one is not specified. If you omit BUFNI from AMP and from the ACB macro instruction, VSAM uses as many index buffers as the STRNO subparameter number; if you omit both BUFNI and STRNO, VSAM uses 1 index buffer.

If data access is through the ISAM interface program, specify for the BUFNI number 1 more than the STRNO number, or specify 2 if you omit STRNO, to simulate having the highest level of an ISAM index resident. Specify a BUFNI number 2 or more greater than the STRNO number to simulate having intermediate levels of the index resident.

BUFSP=number

Specifies the maximum number of bytes for the data and index buffers in the user area. This value overrides the BUFSP value specified in the ACB or GENCB macro, or provides a value if one is not specified.

If BUFSP specifies fewer bytes than the BUFFERSPACE parameter of the access method services DEFINE command, the BUFFERSPACE number overrides the BUFSP number.

CROPS=NCK

CROPS=NRC

CROPS=NRE

CROPS=RCK

Requests a checkpoint/restart option. For more information, see z/OS DFSMSdfp Checkpoint/Restart.

NCK: Requests no data set post-checkpoint modification tests.
NRC: Requests neither a data-erase test nor data set post-checkpoint modification tests.
NRE: Requests no data-erase test.
RCK: Requests a data-erase test and data set post-checkpoint modification tests. If the CROPS subparameter is omitted, RCK is the default.

If you request an inappropriate option, such as the data-erase test for an input data set, the system ignores the option.

FRLOG=NONE

FRLOG=REDO

Specifies if VSAM batch logging will be performed for your VSAM data set.

NONE: Disables the VSAM batch logging function for your VSAM data set. Changes made by applications will not be written to the MVS™ log stream indicated on the LOGSTREAMID parameter.
REDO: Enables the VSAM batch logging function for you VSAM data set. Changes made by applications will be written to the MVS log stream indicated on the LOGSTREAMID parameter.

Note:

If FRLOG=REDO is specified, the LOGSTREAMID parameter must be specified for the VSAM data set(s). If LOGSTREAMID is not specified, IEC161I is issued.
There is no default JCL value for FRLOG. If FRLOG is omitted, the catalog value will be used.

OPTCD=I

OPTCD=L

OPTCD=IL

Indicates how the ISAM interface program is to process records that the step’s processing program flags for deletion.

I: Requests, when the data control block (DCB) contains OPTCD=L, that the ISAM interface program is not to write into the data set records marked for deletion by the processing program.
If AMP=('OPTCD=I') is specified without OPTCD=L in the DCB, the system ignores deletion flags on records.
L: Requests that the ISAM interface program is to keep in the data set records marked for deletion by the processing program.
If records marked for deletion are to be kept but OPTCD=L is not in the DCB, AMP=('OPTCD=L') is required.

Note: This parameter has the same meaning and restrictions for the ISAM interface as it has for ISAM. While it was not required in the ISAM job control language, you should code it in the AMP parameter.
IL: Requests that the ISAM interface program is not to write into the data set records marked for deletion by the processing program. If the processing program had read the record for update, the ISAM interface program deletes the record from the data set.
AMP=('OPTCD=IL') has the same effect as AMP=('OPTCD=I') coded with OPTCD=L in the DCB.

RECFM=F

RECFM=FB

RECFM=V

RECFM=VB

For data sets with SMS, see the DD RECFM parameter described in .

Identifies the ISAM record format used by the processing program. You must code this RECFM subparameter when the record format is not specified in the DCB.

Note: This parameter has the same meaning and restrictions for the ISAM interface as it has for ISAM. While it was not required in the ISAM job control language, you should code it in the AMP parameter.

All VSAM requests are for unblocked records. If the processing program requests blocked records, the ISAM interface program sets the overflow-record indicator for each record to indicate that each is being passed to the program unblocked.

F: Indicates fixed-length records.
FB: Indicates blocked fixed-length records.
V: Indicates variable-length records. If no RECFM is specified in the AMP parameter or in the DCB, V is the default.
VB: Indicates blocked variable-length records.

STRNO=number

Indicates the number of request parameter lists the processing program uses concurrently. The number must at least equal the number of BISAM and QISAM requests that the program can issue concurrently. If the program creates subtasks, add together the number of requests for each subtask plus 1 for each subtask that sequentially processes the data set. This value overrides the STRNO value specified in the ACB or GENCB macro, or provides a value if one is not specified.

SYNAD=module

Names a SYNAD exit routine. The ISAM interface program is to load and exit to this routine if a physical or logical error occurs when the processing program is gaining access to the data set.

The SYNAD parameter overrides a SYNAD exit routine specified in the EXLST or GENCB macro instruction that generates the exit list. The address of the intended exit list is specified in the access method control block that links this DD statement to the processing program. If no SYNAD exit is specified, the system ignores the AMP SYNAD parameter.

TRACE=(subparameter[,subparameter]...)

Indicates that the generalized trace facility (GTF) executes with your job to gather information about the opening, closing, and end-of-volume processing for the data set defined on this DD statement. You can use the interactive problem control system to print the trace output; see z/OS MVS IPCS User's Guide.

The TRACE subparameters are: HOOK, ECODE, KEY, PARM1, and PARM2. See z/OS DFSMS Using Data Sets for full information on the TRACE subparameter and the VSAM trace facility, which you use to obtain diagnostic information during VSAM processing.

ACCBIAS=USER

ACCBIAS=SYSTEM

ACCBIAS=DO

ACCBIAS=DW

ACCBIAS=SO

ACCBIAS=SW

Specify one of these six values to override record access bias in the data class in order to use System-Managed Buffering (SMB) without changing the data class. See z/OS DFSMS Using Data Sets z/OS DFSMS Using Data Sets for details on System-Managed Buffering.

USER: Obtain buffers the same way the system would without SMB. This is the default if you code no specification for the ACCBIAS subparameter.
SYSTEM: Force SMB and let the system determine the buffering technique based on the ACB MACRF and storage class specification.
Note: USER and SYSTEM are the only values you may use to specify record access bias in the data class.
DO: SMB with direct optimization.
DW: SMB weighted for direct processing.
This option provides the capability to use hiperspace.
SO: SMB with sequential optimization.
SW: SMB weighted for sequential processing.

SMBDFR=Y or SMBDFR=N

With direct optimization, use this subparameter to instruct VSAM whether to defer writing of changed buffers to the medium until either the data set is closed or the buffers are required for some other request. See z/OS DFSMS Using Data Sets for further details on using SMBDFR.

SMBHWT=nn

Specify a requirement for hiperspace where nn is an integer from 0 to 99. Use this parameter with direct optimization. The default value is 0, which means that the system does not obtain any hiperspace.

SMBVSP=nnK or SMBVSP=nnM

Specify the amount of virtual buffer space to acquire for direct optimized processing when opening the data set, where nn is 1 to 2048000 kilobytes or 1 to 2048 megabytes.

MSG=SMBBIAS

When you specify MSG = SMBBIAS, the system issues message IEC161I to indicate which access bias SMB has chosen. If SYSTEM is specified in ACCBIAS or Record Access Bias, then the system will choose an access bias for SMB, otherwise it will use what the user specified in ACCBIAS. The possible values in the message are DO, DW, SO, SW, CO, CR or ??, where ’??’ means OPEN could not determine which one of the six bias values was used to create the initial control block structure. The default is no message.

RMODE31=ALL

RMODE31=BUFF

RMODE31=CB

RMODE31=NONE

Designate the residency for buffers and control blocks.

This subparameter allows you to specify whether or not to allocate the buffers and control blocks in 31-bit addressable storage. You can use this field independently of SMB. With SMB the default location is in 31-bit addressable storage ("above the 16-megabyte line"). Without SMB, the default is in 24-bit addressable storage ("below the line").

The values you may specify for RMODE31 are:

ALL: —Control blocks and buffers above the line.
BUFF: —Buffers (only) above the line.
CB: —Control blocks (only) above the line.
NONE: —Control blocks and buffers below the line.

When you do not specify ACCBIAS, or when you specify ACCBIAS=USER, if you specify nothing for RMODE31 in either the JCL or the ACB, the system obtains the buffers and control blocks in virtual storage with a 24-bit address.

When ACCBIAS=SYSTEM, if you specify nothing for RMODE31 in either the JCL or the ACB, the system obtains the buffers in storage with an address greater than 16 million bytes.

When you specify CB or NONE for RMODE31, the system obtains the buffers in 24-bit addressable storage.

When you specify BUFF or NONE for RMODE31, the system obtains the control blocks in 24-bit addressable storage.

If your program runs in 24-bit mode and you use locate mode processing for the VSAM data set, you must obtain the buffers and control blocks in 24-bit addressable storage.

Note: If your program runs with local or global shared resources (LSR/GSR) and uses journaling (JRNAD) or user processing (UPAD) exit routines, the exits must run in 31-bit mode if you obtained the control blocks above the line.

This capability to allocate above the line is necessary when either or both of the following conditions exists:

The number of data sets open to a job is quite large.
The number of buffers is such as to cause a storage shortage if kept in 24-bit addressable storage.

You may specify RMODE31 only with the JCL DD AMP parameter or in the ACB. The RMODE31 subparameter of AMP overrides any RMODE31 values specified in the ACB.

The RMODE31 subparameter is available for all data set types.