i have a question concerning large data volumes.
At H1 our data is split in approx 200 MB files which are stored on tape
and can be retrieved via fpack. Is it possible to do it in a similar way
in root ?
Of course it would be possible to write N events to a files, so that the
files has an approximate size of 200 MB, but if i want to plot one variable
i would have to copy each file from tape (which is the slowest step) and
add up the distributions calculated for each file. It would be more clever,
if one would have one branch of the TTree in one file, so that i
would have to stage one file only (and maybe the files containing the
tree structure). Is there a way in root to make this automatically ?
(i.e. opening a TFile with a TTree containing several branches results in
serveral files, each of them containing only a few branches ?)
Ciao
Thomas
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Thomas Hadig, Ottensen, Donnerstr. 20, D-22763 Hamburg (++49 40 39901186)
office : I. Phys. Institut AAC, Room 1c354, Notkestr. 85, D-22603 Hamburg
hadig@rwth-aachen.de Tel. ++49 40 8998 2312
http://www-h1.desy.de/~hadig/ FAX ++49 40 8998 4385
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