CA Dynam for VSE User Guide

Using CA Dynam/T
• Speed up the positioning for tape cartridge devices.
• Use the Tape Status Display for tape drive and volume information.
• Read stacked standard and nonstandard files in ascending, but not
necessarily sequential, order.
Multifile Positioning and Locating
CA Dynam/T uses the READ BLOCKID and LOCATE BLOCK channel commands
for positioning and locating files within multifile data sets for tape cartridges.
This facilitates tape reel positioning for multifile data sets that contain
nonstandard file structures.
When a file is created on a tape cartridge, CA Dynam/T issues the READ
BLOCKID command to retrieve the physical location and the logical block
position of the file. This information is stored in the CA Dynam Catalog. When
the file is requested for input, CA Dynam/T uses that information to issue a
LOCATE BLOCK command. The same method is used to position a tape to the
end of current files on a volume when writing the second or subsequent file in
a multifile data set.
Stacking Files
Standard and nonstandard files can be stacked on the same tape. For
example, VSAM and non-VSAM files can be backed up to the same tape. Thus,
you can avoid creating largely empty tapes on tape cartridges.
The Status Display
CA Dynam/T uses the status display to communicate volume and drive
information. This display is updated during the following times during
CA Dynam/T processing:
• During AVR (when a drive is eligible for AVR), up to the point when a tape
is selected for use
• When the CA Dynam/T STATUS command is issued
• During final input/output processing for controlled, unlabeled volumes or
for volumes initialized on the fly
Format:
iiiiii u
or
iiiiii f
Chapter 2: Maintaining Tape Files 2–47