Trip Report

Overview of CCS software

We started by reviewing the existing CCS software developed in Paris. Major components of the system include:

• 3 Java Message Service (JMS) buses that support transport of
  • Commands
  • Status/Alarm messages
  • Logging
    • The system is not locked to a specific JMS implementation but CCS currently favors glassfish
• An OCS Bridge which
  • Accepts hight level commands from the telescope and generates sequences of low level CCS commands
  • Sends aggregate monitoring/status information back to telescope
• History Database
  • Uses hibernate to support any backend database
• Subsystems
  • Control/Monitor specific hardware module via one of
    • Java->JNI->C-cpde
    • Java->Serial ports
      • CCS group favours the use of Can bus/Can Open (also used by auger)
  • Communicates with other subsystems via JMS buses
  • Subsystems can optionally consist of reusable modules
    • Modules are wired together using an XML configuration file
      • Currently implemented using Spring by generating spring XML from user-written XML
• Aspect oriented system (currently using AspectJ) can be used to enforce security
  • (e.g. to prevent certain methods from being called unless subsystem is in a particular state)

A guiding principle of the design/architecture is to define CCS specific interfaces which hide implementation details to prevent lock-in to a particular implementation. The CCS software is initially targeted at a PC 104 hardware platform running Linux and Java.

Possible SLAC Contribution to CCS

It would appear that the SCA Data Handling groups SCA Data Handling group's expertise in supporting Java infrastructure and distributed collaborative development, trending databases , swing GUI and web based development could be of immediate benefit to the CCS software. In addition the group is anxious to begin to try the software connected to real hardware and the SLAC effort on the LSST camera shutter seems a natural place to start.

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