Communication, Processing & Archival (CPA)

CPA wiki page (CERN only)

The BE-CSS Communication, Processing & Archival (CPA) section is responsible for providing systems and services, to: allow the different layers and elements of the control system to communicate with one another; process acquired data for a variety of different use cases; archive data to support diagnostics and analysis of beam and equipment performance and behaviour over the lifetime of the CERN particle accelerators.

More specifically, CPA provides communication middleware (RDA3, DIP) with role-based access control (RBAC), data processing platforms for end-users (UCAP), data acquisition and archival platforms with data repositories (NXCALS, Tracing), and application-specific data processing systems (SIS, PMA, BPT, LASER, C2MON, concentrators). Most of these systems provide GUIs and/or programming APIs to end-users. 

The CPA section takes a leading role to ensure a common approach to communication within the control system including consistent data representations and behaviour via the various supported mechanisms and libraries. CPA also strives to provide data processing solutions which can avoid duplication of efforts and minimise the effort required by end-users to achieve the required level of data processing for a variety of use cases.

In order to deliver complete and coherent solutions for end users, the CPA section plans developments in-synch with other CSS sections and in function of global priorities of the group. CPA works in close collaboration with the GTA section to provide the graphical interfaces serving as interactive entry points to CPA services. CPA relies on software engineering technologies provided by the SET section. Finally, CPA also works in partnership with the CERN IT department which provides the underlying storage systems behind the CPA data repositories. CPA is not responsible for data entry or the quality of entered data, beyond what the CPA systems can programmatically validate.

CPA stakeholders are spread across the Accelerator & Technology Sector (ATS), including Operations teams, accelerator physicists and equipment specialists. CPA also interacts with the LHC experiments to ensure a suitable means of data exchange with the CERN accelerator controls infrastructure. Besides providing best-effort support for all operational services, CPA engages with stakeholders, to take into account evolving requirements as well as advise and support on how best to use CPA systems and services.