1. Raw Event Conversion Service in BOSS framework
Zhangxiaomei

2. Content
brief introduction of Boss framework which is completely based on Gaudi
Gaudi main terms
The relationship among them (Gaudi object diagram)
Raw Event Conversion Service
Conversion Service and Converters
The conversion process
The design of Raw Event Conversion Service

3. Gaudi main terms Application Manager Algorithm (like modules in belle)
steering the data processing, such as creating and maintaining the required services and algorithms, implementing the event loop with event selector, executing the algorithms in sequences.
Algorithm (like modules in belle)
Atomic data processing unit
Data Object and Transient Data Store(based on object-oriented data management system)
Atomic data unit (visible and managed by transient data store)
repository for data objects (concerned about data organiztion, life cycle, data indentification, …)

4. Gaudi main terms Services
Globally available software components providing specific functionality
four frequently used service provided by framework: Event Selector;Message Service;JobOptions Service;EventData Service
Converter
Provides conversion from/to persistent data format to/from transient data format.

5. Gaudi Object Diagram
Converter
Application
Manager
Converter
Converter
Event
Selector
Transient Event Store
Data
Files
Message
Service
Persistency
Service
Event Data
Service
JobOptions
Service
Algorithm
Algorithm
Algorithm
Data
Files
Transient Detector
Store
Particle Prop.
Service
Persistency
Service
Detec. Data
Service
Other
Services
Application Manager is the most import component in framework, who bootstrap and control the data processing, such as creating and maintaining the required services and algorithms, implementing the event loop with event selector, executing the algorithms in sequences.
Event Selector is used for event selection, it knows which is the next event.
Message Service outputs the message info.
JobOptions service is to supply options for clients during running time, such as algorithm executing sequence, etc.
EventData Service manages the transient data store, including retrieves and registers data objects to the transient data store.
Data
Files
Transient
Histogram Store
Persistency
Service
Histogram
Service
This object diagram shows the relationship among objects during gaudi framework running time.

6. Raw Event conversion service
The purpose of this service:
Two packages which are involved in this function are EFTDREventCnv and eformat.
Raw Event data object in TDS
ByteStream in files or other sources

7. Data accessing and conversion service
Unsuccessful if requested object is not present
Data Store
Data
Service
(2) Search in Store
Algorithm
(3) Request load
Persistency Service
(1) Retrieve object
Converter
(4) Request creation
Conversion
Service
Request dispatcher Objy, ROOT,..
(5) Register
Understanding Data Stores: Loading
Whenever client requests an object from the data service the following sequence is invoked:
The data service searches in the data store whether the transient representation of the requested objects already exists. If the object exists, a reference is returned and the sequence ends here.
Otherwise the request is forwarded to the persistency service. The persistency service dispatches the request to the appropriate conversion service capable of handling the specified storage technology. The selected conversion service uses a set of data converters - each capable of creating the transient representation of the specified object type from its persistent data.
The data converter accesses the persistent data store, creates the transient object and returns it to the conversion service.
The conversion service registers the object with the data store, the sequence completes and the object is returned to the client. Once registered with the corresponding data store, the object knows about its hosting service.

8. Main class in RawEvent Conversion Service
IConverter
clID( );
createObj( );
createRep( );
IConversionSvc
EventCnv
EventDigiCnv
EFTDREventCnvSvc
mdcDigiCnv
MuonDigiCnv
EmcDigiCnv
TofDigiCnv
IOpaueAddress
clID( )
EFTDREventAddress
One Converter object with one OpaqueAddress object, only Converters know how to decode his opaque Address
Pass around the transient data service,the persistency service and the conversion service, so is used to carry some parameters.

9. The sequence in the conversion process—ByteStreamTDS
converter
DB/File
ConversionSvc
OpaqueAddress
clID( )
createObj id
createObj
new
Data object
access
encoding
builder
Data to build data object
Return reference to dataobject

10. classes used in accessing data sources
To build TDS data object
EFTDREventCnv
package
EventSelector
SubdetectorFragment
new
EventIterator
EVENT
FullEventFragment
unpack
access
EFTDREventInputIterator
Data files
eformat
package
fill
access
EFTDREventInputIteratorImpl
access
access
FileStorage
EventSource

11. The sequence in accessing the event source
InputIterator
EventSource
EventSelector
OpaqueAddress
nextEvent
new
nextEvent
nextEvent
new
EVENT
access
files
setEvent
Return reference
Converter

12. Transient Event Identifier and Raw Event Identifier Encodings
13 bits
E/w
theta
phi
Raw Event ID
32 bits
Emc flag
null
E/w/B/C
theta
phi
Transient Event ID

13. Using tables to do the mapping between REId and TEId
INDEX
TEID
INDEX
TE2RE
RE2TE

14. Transient data objects and Raw Event Digits transformation
Data files
Raw Event digit
MdcREBuilder
Builder
MdcTEBuilder
Transient data Object
Identifier( );
Data( );
rec
TE to RE
Identifier
RE to TE

15. Raw Event Structure in TDS

16. The Digi Data Object class
MdcDigi:
Identifier getID( );
Int getData( );
EmcDigi:
TofDigi:
MuonDigi:

17. Classes in eformat FullEventHeader FileStorage FullEventFragment
RawMemoryStorage
Storage
SubdetectorFragment
GzFileStorage
SubdetectorHeader
Data Collection

18. Function in eformat: bytestream packing and unpacking
data
SubdetectorFragment
Subdetector header
Fullevent
header
FulleventFragment
Storage
(1)Get an event
(2)Separate into two parts
(3)Separate into two parts again
Unpacking
packing