Frequently users will guess at how much SPACE to specify in jcl for a
new dataset. Adding to the confusion is the lack of knowledge about
dasd device types, cylinder and track sizes, etc...
The following example will determine the proper space to allocate based
on the number of records and average record size. This feature became
available in April '96 when SMS (System Managed Storage) was activated
for TMM.
The first value in the SPACE parm indicates the average record length,
137 bytes. The AVGREC value of K indicates that the primary and
secondary values are in thousands (1024), therefore the job is
requesting space for approximately 80,000 records primary and 5,000
records secondary.
The AVGREC parm can accept:
U - number of records
K - number of records in thousands
M - number of records in millions
//STEP010 EXEC PGM=IDCAMS
//SYSPRINT DD SYSOUT=*
//SYSUT1 DD DSN=Z03AF.GDG.SYSLOG(-1),DISP=SHR
//SYSUT2 DD DSN=Z03AF.PSV.SYSLOG,DISP=(NEW,CATLG),
// UNIT=DISK,SPACE=(137,(80,5)),AVGREC=K,
// LRECL=137,DSORG=PS,RECFM=VBA
//SYSIN DD *
REPRO INFILE(SYSUT1) -
OUTFILE(SYSUT2)
/*