[rrd-developers] implementing portable format
tobi at oetiker.ch
Tue Apr 7 22:49:21 CEST 2009
Today Sebastian Harl wrote:
> On Tue, Apr 07, 2009 at 10:25:30PM +0200, Tobias Oetiker wrote:
> > Today Bernhard Reutner-Fischer wrote:
> > > This is really not concerned with the architecture in any way.
> > >
> > > You would just read any data back with the appropriate per data accessor
> > > from libc. like e.g.:
> > as I said, integers are no problem whatsoever, the differences lie
> > in floatinpoint formats and data alignment.
> Data alignment happens in (main) memory only, so this is not an issue
> for on-disk formats. You might just not be able to simple copy a whole
> struct to disk but need to write each field one by one.
Yes, this is clear, but the 'old' data is aligned and we have to be
able to read that. I was under the impression that bernhard had an
idea which would enable us to enable rrdtool 1.5 to access data
from all architectures rrd formats cross platform ...
For the new format, my idea was to use 64bit aligned structs, but
just writing the individual values might a safer aproach sind it
will decouple us enitrely from local data alignment.
Tobi Oetiker, OETIKER+PARTNER AG, Aarweg 15 CH-4600 Olten, Switzerland
http://it.oetiker.ch tobi at oetiker.ch ++41 62 775 9902 / sb: -9900
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