VMS machine – all minidst, all software, sitting in computer center
Problems of long term storage
Observation
Problem with Jazelle format for long-term data preservation
No documentation on IO format
Objects can only be read with (single) Fortran program
2000 line Java program to document low-level format
Virtualization/Cloud to the rescue?
Lessons learned
Data format should be portable, simple to read
Comparison with other fields
FITS
Ample low level documentation on data format
Many implementations available
HDF5
Ample low level documentation on data format
Many implementations available
LCIO
Documentation on low level format
Several implementations available
ROOT
No documentation available
Single program, tight coupling to C++
Conclusion
For root to be viable option for long-term data storage detailed documentation needs to be generated on low level IO format – either by ROOT team, or as part of work of long-term storage working group.