Vault is a commercial, proprietary revision control system by SourceGear LLC which markets its product as a replacement for Microsoft's Visual Source Safe.
The Vault revision control system uses Microsoft SQL Server as a back end database and provides atomic commits to the revision control system.
The tool is built on top of Microsoft .NET, and offers a UNIX client based on Mono.
Fortress, originally an application lifecycle management (ALM) product marketed separately for use with Vault, was later merged into Vault releases.
Third party products have been designed to be integrated with Vault such as OnTime, FogBugz, TeamCity, and SmartBear CodeCollaborator.