What's max_object_size for?

Hi,

I don't understand the use of parameter max_object_size.
does max_object_size mean the max file cache size 
in linux?No matter what's value  I set for TUX, TUX always
works properly.

I found the deault value for max_object_size is 0, what does
this mean? TUX 2.0 reference says the default value for 
max_object_size should be 100MB and the explanation about
this is "Maximum file size TUX is willing to serve".I can't understand
what this mean? If the size of a file exceed 100 MB, TUX 
will refuse such kind of request?

If so, why some report issued by DELL says TUX in
a 2 GB memory machine can serve a 9 GB file?

BTW, someone says the basic unit for max_object_size
is KB instead of MB. So if I set 100 to max_object_size,
TUX will refuse all those files whose size is larger than
100KB. Is this correct?

My final questions are whether max_object_size is 
for file size of http request or for cache size of Linux
file system? 

If first case, is it for total size of files or for individual file size? 

If second case, is it for total size of cached pages or for 
individual cached page size?

Thanks.

Liang Yang