Examples of changing the default values of the unit attribute

The following examples show how you can modify the IBM-supplied defaults for your own environment. You can alter instructions by typing over existing data, or you can add more VSF2UNIT and VSF2DCB macro instructions.

Example 1

In this example, the device name SYSSQ is specified for dynamically allocated data sets and a unique set of DCB attributes is assigned to units 1 through 4. The DCB information for both sequential formatted and unformatted files that are written on these units is indicated in the first VSF2DCB macro instruction (USERDCB) shown in Figure 1.

Figure 1. Modified IBM-supplied macro instructions (example 1)

AFH5VUAT  VSF2UAT    DEVICE=SYSSQ
          VSF2UNIT   (1,4),DCBSET=USERDCB
          VSF2UNIT   5,DCBSET=DCBRDR
          VSF2UNIT   6,DCBSET=DCBPRT
          VSF2UNIT   7,DCBSET=DCBPUN

USERDCB   VSF2DCB    SFRECFM=FB,SFLRECL=50,SFBLKSI=250,SFMAXRE=200,
                     SURECFM=FB,SULRECL=50,SUBLKSI=250,SUMAXRE=200,
                     DMAXRE=200

DCBRDR    VSF2DCB    SFRECFM=F,SFLRECL=80,SFBLKSI=80,
                     SURECFM=F,SULRECL=80,SUBLKSI=80

DCBPRT    VSF2DCB    SFRECFM=UA,SFLRECL=133,SFBLKSI=133

DCBPUN    VSF2DCB    SFRECFM=F,SFLRECL=80,SFBLKSI=80,
                     SURECFM=F,SULRECL=80,SUBLKSI=80

          VSF2DCB    SFRECFM=U,SFLRECL=800,SFBLKSI=800,SFMAXRE=100,
                     SURECFM=VS,SULRECL=-1,SUBLKSI=800,SUMAXRE=100,
                     DMAXRE=100

          VSF2UAT    TYPE=FINAL

Note: The preceding format is given for readability purposes. Remember to add the necessary continuation flags in column 72, and to begin continued lines in column 16.

VSF2UAT, VSF2UNIT, and VSF2DCB must all be coded, in that order, followed by the VSF2UAT TYPE=FINAL statement.

Example 2

To change the unit numbers of the standard input unit, the error message unit, the print unit, and the punch unit, to 1, 2, 3, 4, respectively, modify the IBM-supplied macros as shown in Figure 2.

Figure 2. Modified IBM-supplied macro instructions (example 2)

AFH5VUAT  VSF2UAT    DECIMAL=PERIOD,
                     READER=1,
                     ERRMSG=2,
                     PRINTER=3,
                     PUNCH=4,
                     DEVICE=SYSDA

          VSF2UNIT   1,DCBSET=DCBRDR
          VSF2UNIT   2,DCBSET=DCBTERM
          VSF2UNIT   3,DCBSET=DCBPRT
          VSF2UNIT   4,DCB=DCBPUN