How to open session?
	use static methode  AliRunLoader::Open("galice.root","AlicE","update")
How to retrive pointer to alice run loader:
        use pRICH->GetLoader()->GetRunLoader() (all detector classes inherit from AliDetector wich has GetLoader())
	use methode AliRun::GetRunLoader for gAlice (depricated)
How to get pointers to different root trees:
	TreeE belongs to AliRunLoader, available after AliRunLoader::LoadHeader()
	TreeK belongs to AliRunLoader, available after AliRunLoader::LoadKinematics()
	TreeH belongs to AliLoader   , available after AliLoader::LoadHits()
	TreeS belongs to AliLoader   , available after AliLoader::LoadSDigits()
	TreeD belongs to AliLoader   , available after AliLoader::LoadDigits()
	TreeR belongs to AliLoader   , available after AliLoader::LoadRecPoints()


How to work with the stack of particles?
        - first of all, the stack includes primary as well as secondary particles
	- pointer to the stack is returned by AliRun::Stack() (global gAlice of type AliRun - depricated way to do)
          or by AliRunLoader::Stack() but before one needs to load event header by AliRunLoader::LoadHeader() otherwise both methods return 0.
          Moreover loading header gives the information about number of particles only. 
          To retrive the list of particle one also needs to load kinematics by AliRunLoader::LoadKinematics()        
	- total amount of particles in stack for a given event:         AliStack::GetNtrack() or AliRun::GetEvent() (after LoadHeader())
	- total amount of primiry particles in stack for a given event: AliStack::GetNprimary() or AliLoader::TreeH()->GetEntries() (after LoadHeader())



How to retrive hits:
	Hits a stored on primary by primary basis. To retrieve all hits one needs to do:
	initialise the root tree and containers:    AliLoader::LoadHits() 
	read number of primaries in current event:
	loop on the list of primiries:



How to retrive sdigits? 
	Sdigits stored in tree S with the branch of TClonesArray, all sdigits in a single TClonesArray
	So the tree has only one entry.
	One needs to say:
	pRich->GetLoader()->LoadSDigits(); this one open file, get the tree and invoke AliRICH::SetTreeAddress()    

What are the debug methodes avail:
	AliModule::GetDebug() now depricated, use AliDebug printout instead
	AliModule::SetDebug()
	AliRun::GetDebug()
	AliRun::SetDebug()


How to get info for tid number?
	Header and Kinematics trees must be loaded, then possible to retrive pointer to Stack of particles
	Int_t AliRunLoader::LoadHeader(); Int_t AliRunLoader::LoadKinematics()
	AliStack *AliRunLoader::Stack()
	TParticle *AliStack::Particle(tid)
	TParticle::Print()

How to deal with AliRunDigitizer?
	AliRunDigitizer::Exec() just call AliRunDigitizer::Digitize()	

How to avoid using gAlice?
	Rich()->GetLoader()->GetRunLoader()->GetAliRun() returns gAlice global pointer.