Editing BASIC09 (section)

===Lightweight runtime===
Although it was common to run programs within the BASIC09 environment, as it was in other BASICs, BASIC09 also shipped with a separate run-only version of the code known as Runb. Runb removed the editing and debugging features of the system, and was about half the size of the full BASIC09 as a result.{{sfn|Manual|1984|p=D.1}}

The purpose of Runb was primarily to run PACKed modules when called from other programs. This meant that if the user typed in the name of a BASIC09 module in the OS/9 command line, and that module has been marked as PACKed, it is opened and run by Runb instead of the BASIC09. This reduces memory footprint and improves load time.{{sfn|Manual|1984|p=D.1}}