...
Code and configuration
OpenIFS is a version of the full based on ECMWF's IFS (Integrated Forecast System) code. The first version of OpenIFS is based on Cycle 38R1, the operational model introduced in December 2012 (it has since been superceded for operations)
IFS CY38R1 comprises approximately 1.3 million lines and 5200 files. OpenIFS comprises roughly 0.5 million lines in 2600 files. OpenIFS uses the FCM build software from the UK Met Office to configure and compile the model and is designed to be easy to install on external computer systems.
...
Scientific capability
OpenIFS essentially includes all the same forecasting capability of IFS but without any data assimilation. OpenIFS & IFS are the same with respect to:
...