Notes from  4-JUN-1997 meeting


Messages exchanged during Input buffer management loop 
------------------------------------------------------
Admin -> Worker     Point at slot "K"
Worker -> Admin     I'm now pointing at slot "K"
Admin -> Receiver   Start sending next event
Receiver -> A&W     End of sending event
Worker -> Admin     have finished moving event from fifo to MM

Notes:
- Various scheme exist to implement the "point at slot k".
- Some scheme could possibly totally preallocate buffers and avoid needing an
    explicit message before the next event can be processed.
- Forcing synchronization with explicit message BEFORE the next event is read
    in is a more comfortable idea.


Messages exchanged during event processing loop
-----------------------------------------------
Worker -> Admin     Answer to event in slot "L":
                        pass/fail
                        sptrg pass mask
                        SCL synchronization data 
                            (in particular L1 Geo Sect Trigger Number)
Admin -> L2FW       Advertize answer 

Notes:
- The worker could answer directly to the L2FW, but this does not scale with
multiple worker nodes, AND the Admin needs to know AT LEAST the binary answer


Messages exchanged during VBD management loop
---------------------------------------------
Admin get word count for the processed (and passed) event in slot "M"
Admin sets up short IO pointers for VBD
Admin -> VBD "GO"
VBD ->Admin "finished"
Admin gulp about 10 SCL messages (from 1 to 16?)

Notes:
 - or does the "gulp"  belong right before the "VBD GO"



Admin needs to check
--------------------
    All the pieces of each events against SCL tags. 
    The data stream copy of SCL information matches hardware SCL info.
    The L2 FW decision matches the l2 worker/global answer.

Notes:
 - some or all of this does not necessarily happen synchronously with
 event processing. Synchronization Errors can be reported independently and
 after event processing.

What's in a buffer slot for event N
-----------------------------------
  Inputs from all Preprocessors (including L1FW pipe)
  Real SCL info
  Work area
  Output to L2 HW FW
  Output area to L3
  Error/monitor area
  Buffer slot management state data 
  Event processing state data

What data is included in the L1 FW Preprocessor pipe
----------------------------------------------------
  L1 Geo Sect Trigger Number
  MFP flag (in fact copy ALL SCL trigger qualifiers)
  Mask of L1 Sptrg Fired