Ousterhout's dichotomy is computer scientist John Ousterhout's categorization that high-level programming languages tend to fall into two groups, each with distinct properties and uses: system programming languages and scripting languages – compare programming in the large and programming in the small. This distinction underlies the design of his language Tcl. System programming languages (or applications languages) usually have the following properties: By contrast, scripting languages (or glue languages) tend to have the following properties: