CA Dynam for VSE User Guide

Using CA Dynam/T
• While it is not a requirement that ASSGN statements for tape files be
removed from JCL, it permits full use of Automatic Volume Recognition
(AVR). ASSGN statements for SORT, Westinghouse, Panvalet, and other
utilities that determine DVCTYP before OPEN must be replaced with the
ASSGN function of TDYNASN.
• Tapes must be entered in the Catalog to indicate which volumes are under
control. A unique identifier (TC) is placed in the SYSTEM CODE field of the
VOL1 label of the tape volume. The identifier is written on the tape either
with the DYNCAT INT or INTR commands, or when CA Dynam/T requests
an output scratch tape in normal processing.
In either case, the operator should look at the volume serial number
displayed on the console with the external label on the tape. A new label
should be placed on each tape as it is brought under CA Dynam/T control
so that the operator knows at a glance whether a tape has been initialized.
A utility label print program (TDYNLBL) is provided for this purpose.
• Bring 1400 Emulator tapes and system logical unit tape files under
CA Dynam/T control with the TDYNASN OPEN and CLOSE commands.
Using CA Dynam/T
Controlling Data Sets
CA Dynam/T controls and protects data sets by intercepting all OPEN and
CLOSE requests issued for tape files. Using information in the Catalog file,
CA Dynam/T verifies that the correct tape is being used, as follows:
• For input OPEN requests, a specific volume serial number is required. If it
is not already mounted, a message is issued to the operator instructing
him to mount the required volume.
• For output OPEN requests, a tape that has been initialized under
CA Dynam/T control and listed in the file in scratch status is required.
CA Dynam/T issues a message requesting that a scratch tape be mounted
if it does not find one already mounted. Specific responses to these
messages are discussed later.
• If CA Dynam/T has been activated but is unable to access the Catalog for
any reason, it makes sure that no file is written to a volume that has been
initialized to CA Dynam/T, as determined by the special identification
characters. This protects controlled data sets from being overwritten even
in exceptional situations.
• In response to OPEN requests for tape files that have not been placed
under CA Dynam/T control.
Chapter 2: Maintaining Tape Files 2–7