Version Control and History

See Also

VSS provides version control and history services, to ensure that each version of a file is recoverable. The date/time stamp is used to record when files are checked out or changed. See How VSS Uses the Date/Time Stamp for more information.

VSS uses three methods to track versions of files and projects:

Version numbers. These are internal numbers maintained by VSS. You, the user, have no control over these numbers. Every version of every file and project in VSS has a version number. The version number is always a whole number and always increases.
Labels. These are strings that you can apply to any version of a project or file. A label is a free-form string of up to 31 characters. The following are all valid labels: "1.0", "2.01b", "Field Test 3", and "Approved by QA".
Date/Time stamp. These tell when a file was last modified, or when a file was checked in. VSS supports both 12-hour format (with "a" or "p" suffix) and 24-hour format.

The following table compares and contrasts version numbers and labels.

Version number	Label
Assigned automatically by VSS	Assigned by user, using the Label command from the File menu or the History dialog box
Always a numeric value	Any combination of letters, numbers, symbols, and spaces up to 31 characters
Always increases to next whole number	Anything user assigns
Increases each time an action that affects storage is taken on a file or project such as adding, checking in, or branching	Assigned when user feels that a significant milestone has been reached
Displayed in history, paths, links, share, and file properties dialog boxes and in file pane of VSS Explorer	Displayed in history dialog boxes as a user-supplied string. Indicated by a label icon next to the project name in place of a version number. The user-supplied label string is displayed in the Action column of the History dialog box.
Does not create a new version, simply identifies a new version	Creating a label can create a new version of the file or project and the label is associated with the new version
Cannot be edited or changed by user	Can be edited in the History Details dialog box

Note Some software development groups label VSS with every build. You can get equivalent functionality and less database clutter by doing a history, get at a specific date-time stamp.

For information on how VSS uses the date/time stamp, refer to:

How VSS Uses the Date/Time Stamp