Appendix A About SCCS Mergeable IDs

This appendix explains why SCCS Mergeable IDs (SMIDs) are necessary, how to translate SCCS delta IDS (SIDs) to SMIDs, and how to translate SMIDs to SIDs. It contains the following sections:

• "Why SMIDs Are Necessary"

• "SMID/SID Translation"

  The use of SCCS Mergeable IDs (SMIDs) ensures that every delta is uniquely identifiable, even if its SCCS delta ID (SID) is changed. A SMID is a number generated using the Xerox Secure Hash Function. When you use Freezepointing to create a freezepoint file, it calculates the SMID for both the current delta and the root delta in the SCCS history file. Using both of these values, Freezepointing can identify a delta in a file even if its SID has been changed.

Why SMIDs Are Necessary

This section briefly discusses how Configuring merges SCCS history files. For more information, see Chapter 10, How Configuring Merges SCCS Files."

When Configuring encounters a file conflict during a Bringover Update transaction (file is changed in both the parent and child workspaces), it merges the new deltas from the parent workspace into the SCCS history file in the child. When this merge occurs, the deltas that were created in the child are moved to an SCCS branch off of the delta that both deltas have in common (common ancestor).

When Configuring relocates the child deltas to a branch, it changes their SID. If SIDS were used in freezepoint files to identify deltas, this relocation would invalidate the information contained in the freezepoint file. For that reason, SIDs cannot be used to identify deltas after conflicting SCCS histories have been merged.

SMID/SID Translation

SMID/SID translation is available only through the Freezepointing CLI.

The freezept command sid and smid subcommands enable you to translate specified SIDs into SMIDs, and to translate specified SMIDs into SIDs. The ability to make these translations is useful if you wish to write your own scripts or programs to track deltas.

Translating SIDs to SMIDs

Use the freezept smid command to translate SIDs to SMIDs. The syntax is:

freezept smid [-w workspace] [-r SID] [-a] file

• Use the -r option to specify the SID (in file file) for which you wish to calculate a SMID.

• Use the -a option to calculate a SMID for all of the SIDS in file.

• For convenience you can use the -s option to specify a directory from which file is relative.

Examples

Translating SMIDS to SIDS

Use the freezept sid command to translate SMIDs to SIDs. The syntax is:

freezept sid [-w workspace] [-m "SMID"] [-a] file

• Use the -m option to specify the SMID (in file file) for which you wish to calculate a SID.

• Use the -a option to calculate a SID for all of the deltas in file.

• For convenience you can use the -s option to specify a directory from which file is relative.

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  Note -

  Because the SMID contains white space, you must enclose it within quotation marks.

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Examples