The Atacama Large Millimetre / submillimetre Array (ALMA), located in the Atacama Desert in northern Chile, is the most advanced astronomical interferometer consisting on an array of more than 70 radio telescopes observing at millimetre and submillimetre wavelengths. ALMA is expected not only to obtain detailed imaging of local star and planet formation but also to provide insight regarding the early universe.The ALMA Common Software (ACS) is the software infrastructure used to develop the ALMA distributed software, allowing developers to use a collection of well designed and proved set of patterns, components, services and tools based on a CORBA middleware. Maintenance and improvement of ACS is carried out by a joint team of ESO and GTD engineers.The 11th ACS Workshop was held in the European Southern Observatory (ESO) headquarters in Garching, Germany from the 4th to the 6th of November 2014 counting with GTD as an organizing member; 7 years after the last workshop and coinciding with an operational ALMA major milestone allowing resumption of regular Early Science Observations.Because of the adoption of ACS by a number of other telescopes, the main objective of the workshop was to foster collaboration between ESO and other astronomical projects that use or plan to use ACS to develop their control software.GTD ACS team members presented framework services and tools, and acted as instructors for the hands-on exercises. Two course tracks were organized to cope with the workshop objectives:• The basic track aimed to introduce beginners to control software development over the ACS framework. A series of presentations to introduce ACS architecture, components design and usage details of the most important services and tools were put into practice in a group exercise to develop the control system of a toy telescope.• The extended track aimed to present ACS advanced usage. Presentations about ACS’s advanced services were complemented with discussions of needs and future ACS evolutions motivated by non-ALMA projects.Due to the workshop’s major success and its participant’s positive feedback, a new edition of the ACS Workshop is already being planned for 2015.
