> ok i just performed some more tests and you guys are 
> right, the GET responses during update mode were all 
> 304 except for robots.txt, which is expected i guess. 
> also, total incoming data in update mode was 
> significantly less than mirror mode (3k vs. 42k).
> 
> the site where i saw almost identical download times 
> for mirror vs. update modes was 
> <http://www.oldskool.org/pc/help/oldonnew/>, which as it 
> turned out consisted mostly of .shtml files. NOTE: a 
> file comparison between a redownloaded file 
> (01_intro.shtml) and the original revealed _no_ 
> differences in the files. does this mean that 
> all .shtml files are forced to be redownloaded every 
> time even if they are apparently static?> 
> thanks,
> tom

I am not quite sure what is the SHTML file type
actually, but sometimes a file name extension can be
misleading - as the file could be generated on the fly
by the server, and hence could be re-downloaded
everytime, despite the fact that the content could be
the same.