There was a paper on the web somewhere a few years ago that says what OS C call oracle makes with a db file scattered read and db file sequential read? I don't think I saw this on metalink. I think it is one of the short ones that Jeff Holt wrote , but I can't find it. Its not this one. http://www.geocities.com/ckempster/wpapers/oracle/predictingMultiblockread.pdf