VSS are stencil files created with Microsoft Visio 2007 and earlier. A relatively new file format is .VSSX that was introduced with Microsoft Visio 2013. Stencil files provide drawing objects that can be included in a .VSD Visio drawing. Microsoft Visio itself is known for creating drawing elements such as collection of shapes, connectors, flowcharts, network layout, UML diagrams, software diagrams, database models, objects mapping and other similar information. It also has rich conversion features of Visio documents to other file formats such as PNG, BMP, PDF and others. Visio is available for both Windows and Mac OS.
VSS File Format
Unlike VSSX, which is based on Office Open XML file format, VSS files are based on binary file format.
Initially Visio was produced as a standalone product by Shapeware Corporation in 1992 by its version 1.0. Shapeware Corporation changed the name to Visio Corporation in 1995 to take advantage of the market recognition. Microsoft re-brands Vision in 2000 as Microsoft Office application. Visio for Enterprise Architects was introduced with Visual Studio .NET in 2003 and 2005. Visio 2007 was released on November 30, 2006. Ribbons were introduced in user interface by Microsoft Visio in 2010.