Definitions

• DCS (Distributed Control System): The system framework consisting of GUI/Clients, DCSS, and DHS programs.

• DCS Protocol: The plain text protocol spoken over TCP/IP sockets used between the programs in the DCS framework.

• GUI/client Protocol: Subset of the DCS protocol that is used by DCSS and the GUI/clients.

• DHS Protocol: Subset of the DCS protocol used between DCSS and the DHS programs.

• DCSS (Distributed Control System Server): The centralized server that opens listening ports for GUI/Clients and DHS programs. It acts a message router between the GUI/Clients and the DHS programs. It is also responsible for handling user permissions and storing state of the beam line.

• DHS (Distributed Hardware Server): Any program that speaks the DCS hardware protocol (or subset of it). A typical DHS accepts DCS messages and controls a piece of hardware directly. A DHS may also be used to translate and forward DCS messages to an alternate control system.

• Blu-Ice: SSRL's standard Graphical User Interface used for alligning a beam line and defining/monitoring Protein Crystallography experiments. This program speaks the "GUI/Client" protocol and connects to DCSS.

• Diffraction Image Server: A program that loads and caches diffraction images as requested, returning views of the diffraction image in compressed JPEG format. This is used by Blu-Ice for viewing diffraction images.