how informix archive works?

Hi all, I have some doubt on the informix backup. I'm using ontape command to perform level 0 backup on my Test database (7.31.UC2). The first level 0 backup took around 2 hours to complete and the second time of level 0 backup only took ~45min. The second time of the backup begin right after the first backup completed. There's no other transactions running on the database during the backup. Which means that the data for both archive is exactly identical. My question is why second backup take shorter duration to complete compare to the first backup Does any one of us know where can i obtain the documentation to describe how informix archive works? TIA, miyaki __________________________________ Do you Yahoo!? Yahoo! Domains ' Claim yours for only $14.70/year http://smallbusiness.promotions.yahoo.com/offer sending to informix-list