Completing Backup Range: Last changed date and time

Using the CPYOPT command causes the system to write the last changed date and time of an optical backup volume or directory.

This includes any time that the system wrote files or directory attributes to the directory or volume.

The last changed date and time for that directory and volume always reflects the date and time of the request. This remains true even if the system writes a file to a backup directory.

Scenario 1: Last changed date and time

On 1 July 1999, the user issues the CPYOPT command for directory /DIR1 by specifying *BEGIN as the starting date. If the system successfully copies all the eligible files, then the dates are as follows:
  • The system sets the complete starting date for backup directory /DIR1 to *BEGIN.
  • The system sets the complete ending date to 1 July 1999.
If the system copies at least one file to /DIR1 as a result of this request, the last changed date is also 1 July 1999.

The system does not necessarily update the last changed date and time as the result of a successful copy. If the system did not write any files to the backup directory, the system may update the complete range, but not the last changed date.

Scenario 2: Last changed date and time

In “Scenario 1: Last changed date and time,” the backup directory /DIR1 has the following dates after the request:
  • A starting date of *BEGIN
  • An ending date of 1 July 1999
  • The last changed date of 1 July 1999

On 1 October 1999, the user issues the CPYOPT command again for directory /DIR1. This time the command specifies SLTFILE(*CHANGED) to copy only the files that have changed since the last CPYOPT request. Assume that no files have changed since the last backup on 1 July 1999. Since no files are eligible to copy, the system writes no files to the backup directory /DIR1. Therefore, the last changed date remains 1 July 1999. However, since no eligible files failed, the complete range for /DIR1 expands to have an ending date of 1 October 1999. The last changed date and time becomes most important when it is set beyond the complete range. This happens if some files are actually copied but other eligible files failed to copy for some reason.

Scenario 3: Last changed date and time

In “Last Changed Date and Time — Scenario Two,” the backup directory /DIR1 has the following dates after the request:
  • A starting date of *BEGIN
  • An ending date of 1 October 1999
  • A last changed date of 1 July 1999
On 1 December 1999, the user issues the CPYOPT command again for directory /DIR1. Assume that 10 files were changed or added to primary directory /DIR1 since the last CPYOPT request on 1 October 1999. Assume that only eight files are successfully copied to /DIR1 and that two of the eligible files failed. Since the system did not copy all eligible files, the complete range stays the same with a starting date of *BEGIN and an ending date of 1 October 1999. However, since /DIR1 changed, the last changed date gets updated to 1 December 1999. Since the last changed date is outside the complete range, a complete copy of /DIR1 from *BEGIN to 1 October 1999 may not exist. A more recent copy by the change on 1 December 1999 might have replaced one of those files.