EDM FAQ: Data Formats Introduction
The CDF Run II EDM currently treats three data formats:
- YBOS, as was used in Run I
- SeqRoot, a sequential event access oriented ROOT-based data format. This is
the format in general use nowadays
- FlatRoot, a CDF invention storing ROOT events as raw physical records. This
is used in some cases on-line.
There are a few ways to determine the data format. Experts can use hex dumps of
the first four words in a datafile, for example, to do so. Rather than have to
understand that in detail, one can use an EDM utility
Edm_IdentifyFileFormat
which attempts to open
and read one event assuming each of the above formats until it finds one that
succeeds. This tests not only the format, but also the integrity of the first
event.
There are also utilities to convert YBOS and FlatRoot datafiles to and from
SeqRoot data files. Their names indicate the conversion they carry out.
Comments on this page may be sent to Rob Kennedy