[rrd-users] Date/time-related problem on Windows

[Dod]

Hello,

I have a problem with win32 rrdtool (1.3.8 pre compiled version), I am
rrdtool  beginner  and  used  it  only  once  for multiple temperature
sensors draw so I am not experienced enought to fully understand fully
how this powerfull RRDTool work.

Today  I  want to use RDDTool again to graph HEC / CRC error's counter
of DSL router, so I create a one minute step .rrd with enought rows to
get more than a year of data.

rrdtool create hec.rrd --start "1257698388" --step 60 DS:HEC:GAUGE:600:U:U RRA:AVERAGE:0:1:600000

1257698388 = 08 nov 2009 16:39:48

But if I ask for rrdtool first and last I get weird values :

first = 1221698400 = 18/09/2008 00:40:00 <= 2008 ???
last =  1257698388 = 08/11/2009 16:39:48

I don't understand first and last date, why 2008 , why last is --start
value ?

Now I add a few entries

rrdtool update hec.rrd 1257698606 at 41907 1257698821 at 41907 1257698908 at 41907 1257698933 at 41907 1257698956 at 41907 1257698965 at 41907

1257698606 = 08/11/2009 16:43:26
1257698821 = 08/11/2009 16:47:01
1257698908 = 08/11/2009 16:48:28
1257698933 = 08/11/2009 16:48:53
1257698956 = 08/11/2009 16:49:16
1257698965 = 08/11/2009 16:49:25

And ask first/last again

first = 1221699000 = 18/09/2008 00:50:00 <= 10 minutes diff from previous request ???
last =  1257698965 = 08/11/2009 16:49:25 OK this is real time of last entry

Why first value differ from previous request ?

regards.