Record type 19 is written:
- For each online device associated with a specific IPL time frame,
- For each online device associated with a processed HALT EOD or
SWITCH SMF command, and
- When a direct access volume that is defined by DD statement is
demounted.
This record contains:
- The volume serial number
- The volume table of contents (VTOC) address
- The owner identification
- The unit type
- The number of unused alternate tracks
- The number of unallocated cylinders and tracks
- The number of cylinders and tracks in the largest free extent
- The number of unallocated extents.
- The previous three fields repeated for track-managed
space
- The volume size information
It contains the device number and module identification for devices
having movable plugs.
Note: - Record type 19 is not produced for DOS volumes used under the
operating system.
- In order to determine the latest status of a shared file, the
CPU clocks must be synchronized.