Observing Blocks (OBs) provide a full description of a observation in terms of telescope, instrument and exposure requirements. A full interface exists for ALFOSC, NOTCam and FIES observations. The software needed to translate such an OB description into a set of executable sequencer commands has been developed for the ALFOSC ``Imaging'' and ``Spectroscopy'' modes and is being tested. The compiler modules for the remaining instruments/modes will be developed and tested during the coming months.
A interface that allows to control the execution of an OB in a verbose mode is being developed in parallel. This ``executer'' system will include a graphical interface that allows to execute as a whole, or in parts the resulting set of sequencer commands and scripts defined by the OB, with the option to stop or pause at intermediate steps, skip certain parts or abort execution at any time.