The FTP server allows a client program to dynamically allocate
a new physical sequential data set, a partitioned data set (PDS),
or a partitioned data set extended (PDSE), for the purpose of transferring
data to be written to that data set. The following optional allocation
variables can be used to override and turn off the defaults that affect
the allocation of the data set.
- Variable
- FTP.DATA statement
- allocation units
- SPACETYPE
- blocksize
- BLKSIZE
- data class
- DATACLASS
- directory blocks
- DIRECTORY
- data set name type (physical sequential data sets only)
- DSNTYPE
- extended attributes
- EATTR
- logical record length
- LRECL
- management class
- MGMTCLASS
- model DCB values
- DCBDSN
- PDS type
- PDSTYPE
- primary space
- PRIMARY
- retention period
- RETPD
- secondary space
- SECONDARY
- space type
- SPACETYPE
- unit count
- UCOUNT
- volume count
- VCOUNT
- record format
- RECFM
- retention period
- RETPD
- storage class
- STORCLASS
- unit
- UNITNAME
- volume serial number or list
- VOLUME
Some of these allocation variables might provide duplicate information.
For example, the model DCB might have a record format (RECFM) that
differs from the record format specified by a data class and from
the one explicitly specified by the client. FTP passes all variables
that are specified to dynamic allocation and lets it determine which
of the specifications take precedence. The following list describes
the exceptions to that policy:
- If neither the primary nor secondary space quantity is specified,
the allocation units value is not sent.
- If the data set organization is physical sequential, directory
blocks specification is not sent.
- Otherwise, all variables are sent to dynamic allocation where
the order of precedence is:
- Any FTP.DATA statements or SITE parameters explicitly specified
or specified by default
- Any attributes picked up from the model DCB and not otherwise
explicitly specified
- Any attributes picked up from the data class and not previously
derived from 1 or 2
- Any allocation defaults