Partitioned Concatenation

Concatenated UNIX directories are processed with a DSORG=PO in the DCB. When UNIX directories are concatenated, the system treats the group as a single data set. A partitioned concatenation can contain a mixture of PDSs, PDSEs, and UNIX directories in any order. Partitioned concatenation is supported only when the DCB is open for input.

There is a limit to how many DD statements are allowed in a partitioned concatenation. The sum of PDS extents, PDSEs, and UNIX directories must not exceed the concatenation limit of 255. Each UNIX directory is counted as 1 toward this concatenation limit. For example, you can concatenate 15 PDSs of 16 extents each with 8 PDSEs and 7 UNIX directories ((15 x 16) + 8 + 7 = 255 extents).

Figure 1 shows an example of a partitioned concatenation of PDS extents, several PDSEs, and two UNIX directories, for a total of 255 extents.

Figure 1. A Partitioned Concatenation of PDS extents, PDSEs, and UNIX directories

//DATA01  DD DSN=XPM17U19.PDS001,DISP=SHR,VOL=SER=1P0101,UNIT=SYSDA
//        DD DSN=XPM17U19.PDS001,DISP=SHR,VOL=SER=1P0101,UNIT=SYSDA
//        DD DSN=XPM17U19.PDS001,DISP=SHR,VOL=SER=1P0101,UNIT=SYSDA
//        . . . 
//        DD DSN=XPM17U19.PDSE01,DISP=SHR,VOL=SER=1P0101,UNIT=SYSDA
//        DD DSN=XPM17U19.PDSE01,DISP=SHR,VOL=SER=1P0101,UNIT=SYSDA
//        DD DSN=XPM17U19.PDSE01,DISP=SHR,VOL=SER=1P0101,UNIT=SYSDA
//        DD DSN=XPM17U19.PDSE01,DISP=SHR,VOL=SER=1P0101,UNIT=SYSDA
//        DD PATH='/sj/sjpl/xsam/xpm17u01/',       # two UNIX directories
//           PATHDISP=KEEP,FILEDATA=TEXT,
//           PATHOPTS=(ORDONLY)
//           RECFM=FB,LRECL=80,BLKSIZE=800
//        DD PATH='/sj/sjpl/xsam/xpm17u02/',
//           PATHDISP=KEEP,FILEDATA=TEXT,
//           PATHOPTS=(ORDONLY)
//           RECFM=FB,LRECL=80,BLKSIZE=800

Concatenated UNIX directories are always treated as having like attributes, except for block size. They use the attributes of the first file only, except for the block size. BPAM OPEN uses the largest block size among the concatenated files. All attributes of the first data set are used, even if they conflict with the block size parameter specified.