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FEE Control. DIM (Distributed Information Management ) as communication layer between TPC/TRD and FEE control/monitoring application at ALICE. Topics. DIM principle and DIM in FEE Control DIM Communication DIM Server / Service DIM Client DIM – Data
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FEE Control DIM (Distributed Information Management) as communication layer between TPC/TRD and FEE control/monitoring application at ALICE.
Topics • DIM principle and DIM in FEE Control • DIM Communication • DIM Server / Service • DIM Client • DIM – Data • FEE Command (DIM – Command)
DIM @ ALICE (overTCP/IP) FEE-Controler - DIM-Client Request Service Name-Server - DIM_DNS_NODE Service Info Register Service Subscribe to Service Service Data Commands RCU with µClinux - DIM-Server
DIM - Communication The client subscribes to a service once and gets back the corresponding data via a callback-function (timed and/or monitored)
Server • DIM - Server: • the server is represented by servername (must be unique) - the server can offer several services • DIM - Service: • data (base or complex), the server provides to clients - the service is specified by the servername combined with the servicename (e.g. servername/servicename|type|).
Client DIM - Client: - is represented by PID@hostname - has to know servername and servicename to ask DIM – Nameserver for connection point to server. - can send commands to server as base-data-types (like int, char, long, short, float or double) or complex types (like strings or struct-like-objects).
DIM – Data (overTCP/IP) Ethernet-Header IP-Header TCP-Header DIM-Header DIM-Data (Service or Command)
Command Command as character-string of variable length: 0 31 Bits ID Payload - Size Flags (Verify - Flag, ACK - Flag) ACK - ID Payload . . .
Command With the Command you can do: • Huffman coding to minimize traffic • use payload to transfer data from client to server • use payload to send instructions to server - use to reinstall certain settings after reboot of RCU