Protection of access to BSAM or BDAM data sets

The LABEL parameter can modify the data set processing through the IN and OUT subparameters, as indicated in Table 1, if the assembler OPEN macro instruction specifies the data set processing as:

When using the basic sequential access method (BSAM): INOUT, OUTIN, OUTINX, or EXTEND
When using the basic direct access method (BDAM): UPDAT

The LABEL subparameters are coded:

  
   //ddname DD LABEL=(data-set-sequence-number,label,PASSWORD,IN)  
   //ddname DD LABEL=(,label,PASSWORD,OUT)  
   //ddname DD LABEL=(,,NOPWREAD,IN)  
   //ddname DD LABEL=(,,,OUT)

Table 1. Processing with DD LABEL Subparameter IN or OUT
OPEN macro parameter	LABEL subparameter	Program processing of data set	Required password
INOUT (BSAM) UPDAT (BDAM)	IN	Read records (If the program tries to write to the data set, the system gives control to the error analysis (SYNAD) routine.)	Read password, if data set protected with PASSWORD; write password, if data set protected with NOPWREAD
OUTIN (BSAM) UPDAT (BDAM)	OUT	Write records (If the program tries to read the data set, the system gives control to the error analysis (SYNAD) routine.)	Write password, if data set protected with PASSWORD or NOPWREAD
OUTINX (BSAM) EXTEND (BSAM)	OUT	Add records to end of data set (If the program tries to read the data set, the system gives control to the error analysis (SYNAD) routine.)	Write password, if data set protected with PASSWORD or NOPWREAD

Other uses of the LABEL IN subparameter: You can also use the IN subparameter to avoid operator intervention when reading a data set that has an unexpired expiration date.

Data set processing with LABEL OUT subparameter: When the OPEN macro instruction specifies OUTINX or EXTEND and the DD LABEL contains an OUT subparameter, the system adds records to the end of the data set regardless of the DISP parameter of the DD statement.

Examples:

  
//EX1  DD  DSNAME=D.E.F,DISP=OLD,LABEL=(,,NOPWREAD,IN)  
//EX2  DD  DSNAME=EXIST,DISP=MOD,LABEL=(,,PASSWORD,OUT)