The ROOT system is
an
object oriented data analysis
framework being developed at
CERN.
This is a free set of tools
for manipulating and analysing
data from particle accelerators.
Typical data sets are terabytes in size
and the root system
is designed to handle such large data sets.
It is hoped that ROOT will replace/compliment
old FORTRAN tools such as PAW, PIAF and the simulation package GEANT.
ROOT is written in C++
and you can get the software,
or more information from
their homepage at
http://root.cern.ch/.