STAR I/O Classes
The component organization of STAR I/O is supported by STAR I/O classes: sttree,stbranch, stioevent and stfile ( no relation to ROOT ttree and tbranch classes).
Sttree - container of components;
Stbranch - representation of STAR I/O component;
Stioevent - ROOT I/O connection;
Stfile - container of files.
These classes perform I/O, add, fill, update of files/components
They are heavily based on ROOT environment and work well.
However when user modifies the definition of his class and ROOT rewrites
The corresponding streamer method, then previously written data becomes inaccessible. ROOT does not yet support automatic schema evolution.
Schema evolution aside, ROOT I/O is completely sufficient for us.