CA Dynam for VSE User Guide

DYNINFO Parameter List
DYNINFO Request Fields
DYNSTAMP, DYNRQID, DYNRQLEN
These DYNINFO header fields containing the sentinel, release identifier and
parameter list length are required. If DYNINFO is generated with TYPE=CSECT
or TYPE=DS (the default), these fields will contain the correct values at
execution time. However, if generated as a DSECT (TYPE=DSECT), these
values must be initialized as shown by the caller before invoking DYNACC.
If DYNSTAMP is not equal to DYNINFO, DYNACC will set DYNRTCOD to 28.
DYNRQLEN, DYNNVBRS
For data set calls (SD, GD, DD, NG, and NX), for each data set (DYNDBREC)
and version (DYNGBREC) retrieved, DYNACC builds an array of volume/extent
(DYNVBREC) entries in DYNINFO. Usually this starts with volume sequence one
for the file version and continues for as many volumes or extents as exist and
will fit in DYNINFO. If the DD call is used, specifying the DYNRQVSQ
parameter, then the array will commence with the specified volume sequence
number. If the NX call is used, the array will commence with the next volume
in sequence after the last volume returned by the preceding SD, GD, DD, NG,
or NX call.
By default, enough space is reserved in DYNINFO to accommodate twelve tape
volumes for a given data set version. The actual number that may be
accommodated is indicated by the DYNNVBRS field. At assembly time, the
DYNINFOA macro calculates the DYNNVBRS value by dividing the length of
DYNINFO, minus the length of other segments, by the length of a tape
DYNVBREC (DYNVBRLN).
As DYNACC builds DYNINFO while processing each call, the length of each
segment is added to DYNRTLEN. The segment is not moved into DYNINFO if
there is insufficient space to accommodate it. This is determined by comparing
the value in DYNRTLEN with that specified by DYNRQLEN. When DYNRTLEN is
greater than DYNRQLEN, DYNACC sets DYNRTCOD to 28.
DYNRTLEN contains the length in bytes of DYNINFO required to accommodate
all volumes for the requested data set version, starting at the volume
sequence number specified in DYNRQVSQ. (DYNRQVSQ is only valid for DD
calls.) The DD function may be used to retrieve the additional volumes for the
version.
The LEN parameter of the DYNINFOA macro may be used to reserve a greater
or smaller number of bytes for DYNINFO in total. The LEN value specifies the
length reserved for DYNINFO and the value to be placed in DYNRQLEN.
Consequently, a greater or smaller number of VBRs may be accommodated.
The minimum length is equal to the value specified by DYNCOMLN. Calculate
the required value by adding the value specified by DYNCOMLN to the result of
the number of volumes desired, minus one, multiplied by the length of the
appropriate segment (DYNVBRLN for tapes or DYNEXTLN for disk extents).
10–12 User Guide