RE: New and old Files version

> Manuel,
>
> Our principle is to provide back compatibility with files generated at
> any time in the past,
> ie ROOT5.17 must be able to read files written with ROOT1.00 written 10
> years ago.
> Forward compatibility is more difficult to achieve, ie being able to
> read files written with a new version and read them with an old version.
> This will typically works across two production releases.
> I have tested for example that files generated with version 5.17 can be
> read with version 4.04 (ie 5 production releases ago), but these files
> cannot be read by version 4.00 because we introduced a new compression
> algorithm in 4.04.

This is why I tried:

outputFile = new TFile("K0sL020071204.root", "RECREATE", "", 0);

to set compression level to 0! But also this does not work! Is there any way, in your opinion, to play with ClassDef or streamers to bypass any "new feature" when I create the file? It will contain only a TH1D with 200 bins so I'm not afraid of file dimensions (even NO compression is fine)!

Another solution for my problem would be to save bins content in a text file but ... a ROOT file with an histogram ... looks better and it's more portable! :-)

Thanks even if your answer will be ... NO!!! :-)

Bye...

>
> Rene Brun
>
>
> Manuel Mussini wrote:
> >
> > Hi,
> >
> > how can I create a file with version 5.17.02 (Windows) and use it
> > under 4.00/08 (Linux)?
> >
> > I only need to save a TH1D on it!
> >
> > Creating the file with:
> >
> > outputFile = new TFile("K0sL020071204.root", "RECREATE");
> >
> > or:
> >
> > outputFile = new TFile("K0sL020071204.root", "RECREATE", "", 0);
> >
> > I get this error while opening it under ROOT 4:
> >
> > R__unzip: error in header
> >
> > Is there a simple way to get what I want?
> >
> > Bye.
> >
Received on Thu Dec 06 2007 - 13:12:55 CET