# Services

Intended audience: administrators

- Event system
  - Using multicast protocol to transfer events
  - Events in Tango releases lower than 8
- The Tango controlled access system
  - User rights definition
  - Running a Tango control system with the controlled access
- HDB++ - an archiving/historian service
  - HDB++ Design and implementation
  - Event Subscriber interface
  - Configuration Manager interface
  - Legacy HDB tables structure
  - schema SQL source (TimescaleDb)
  - schema SQL source (MySQL)
  - schema CQL source (Cassandra)