Z command

From m204wiki
Jump to navigation Jump to search


File manager (as User 0 only)
Applies deferred updates to a Model 204 file



Usage notes

The Z command applies deferred updates to a Model 204 file. Deferred updates are produced by opening a file in deferred update mode, and then updating the file using the FLOD command or the REORGANIZE command. The Z command performs the following operations:

  • Reads records from the data set pointed to by the SORT5 DD name, FILEDEF, or DLBL.

  • Updates Tables C and D of the currently open Model 204 file.

  • Writes for-each-value records to the data set pointed to by the TAPE5 data set.

Use of SORT5 and TAPE5 may require user authorization by an external security interface.

When processing of the Z command is complete, Model 204 displays various statistics, including the number of index entries added and deleted, and the number of records written to the for-each-value data set.

Use the Z command to rebuild the Ordered Index from deferred update records after issuing the REORGANIZE command.

When it processes a Z command, Model 204 ends any update unit in progress and begins a non-backoutable update unit. For more information about Model 204 update units, see File integrity and recovery.

The Z command and the deferred update feature are described in detail in Deferred update feature.