When you use thewizard to create a Visual SourceSafe database, you have a choice of usage configuration options that represent the work styles possible for your team. Two work styles are supported by Visual SourceSafe:
Lock-Modify-Unlock (also known as the exclusive checkout model)
Copy-Modify-Merge (also known as the multiple checkout model)
The Lock-Modify-Unlock work style is the default work style for a Visual SourceSafe database. Many version control systems use a similar model, which permits only one user at a time to change a file.
Using the Lock-Modify-Unlock work style, Visual SourceSafe copies a file or project from the database to a user's working folder during checkout. The file is locked as far as the database is concerned. If another user attempts to check out the file, Visual SourceSafe generates a message stating that the file is already checked out. When the user checks the file into the database, a new version of the file is created and then unlocked to make it available to other users.
To support team environments, Visual SourceSafe provides a Copy-Modify-Merge work style that enables parallel development. This work style uses the Visual SourceSafe merge mechanism to allow more than one user to check out the same file.
For the Copy-Modify-Merge work style, Visual SourceSafe copies a file or project from the database to a user's working folder during checkout. Another user can also obtain a copy of the item and put it in his or her local working folder. Both users can modify their respective local copies of the file. When one of the users checks the file back in to the Visual SourceSafe database, that version of the file becomes the current version. When the other user who has been sharing the file checks in changes, Visual SourceSafe uses its merge mechanism to display the file differences and allow the user to merge the file contents with the database file contents. For more information, see.