PAD vs. Ntuple
Ntuple: 1000 variables/event = 4KByte/ev (PAD = 60 KB)
High Pt: ? O(1% total data) keep all events
- PAD: 2TBytes, 20 tapes ? analyze at home
- Ntuple: 200 GBytes ? keep on PC hard disk
- but ! Need several versions of the Ntuple, reduce 1/4 at most
Low Pt: ? O(10% total data)
- PAD: 20TB, 200 tapes ? have to do something
- Ntuple: 2TB ? don’t fit on disk !
- Reduce data sample ? 1/10th ? Low-Pt = High-Pt
anyhow is analysis dependent, ,many people... many opinions
still… how do I bring those data in Italy ? Few tens to few TB..