Logical record length and block size
For compiler data sets other than the work data sets (SYSUTn)
and z/OS® UNIX files, you can set
the block size by using the BLKSIZE
subparameter
of the DCB
parameter. The value must be permissible
for the device on which the data set resides. The values you set depend
on whether the data sets are fixed length or variable length.
For fixed-length records (RECFM=F
or RECFM=FB
), LRECL
is
the logical record length; and BLKSIZE
equals LRECL
multiplied
by n where n is equal to the
blocking factor.
The following table shows the defined values
for the fixed-length data sets. In general, you should not change
these values, but you can change the value for theSYSPRINT data set. You can specify BLKSIZE=0
,
which results in a system-determined block size.
Data set | RECFM |
LRECL (bytes) |
BLKSIZE 1 |
---|---|---|---|
SYSIN | F or FB |
80 | 80 x n |
SYSLIB or other copy libraries | F or FB |
80 | 80 x n |
SYSLIN | F or FB |
80 | 80 x n |
SYSMDECK | F or FB |
80 | 80 x n |
SYSOPTF | F or FB |
80 | 80 x n |
SYSPRINT2 | F or FB |
133 | 133 x n |
SYSPUNCH | F or FB |
80 | 80 x n |
SYSTERM | F or FB |
80 | 80 x n |
|
For variable-length records (RECFM=V
), LRECL
is
the logical record length, and BLKSIZE
equals LRECL
plus
4.
Data set | RECFM |
LRECL (bytes) |
BLKSIZE (bytes) minimum acceptable
value |
---|---|---|---|
SYSADATA | VB |
1020 | 1024 |