Description of problem:

SRC packages commonly contain mostly redundant data from revision to
revision.  Since kernel is the most commonly looked at and downloaded
src I will start here. The problem may apply to any series of updated
src.rpms.

for example all current kernel-2.6.9-1.*_FC3.src.rpm packages 
have linux-2.6.9.tar.bz2 (36261440 bytes) in common.  

Version-Release number of selected component (if applicable):

I was comparing 
     kernel-2.6.9-1.678_FC3.src.rpm
  and
     kernel-2.6.9-1.681_FC3.src.rpm

How reproducible:
 very 

Steps to Reproduce:
1. use rpm2cpio and extract the contents of
   kernel-2.6.9-1.678_FC3.src.rpm 
and   
   kernel-2.6.9-1.681_FC3.src.rpm 
into their own dir.

2.compare linux-2.6.9.tar.bz2 in both dirs.
 $ md5sum *-orig/linux*tar.bz2
 e921200f074ca97184e150ef5a4af825  678-orig/linux-2.6.9.tar.bz2
 e921200f074ca97184e150ef5a4af825  681-orig/linux-2.6.9.tar.bz2

3.
  Note that the two packages contain ~36MB of bz2 compressed
data that is identical from update to update to update....
  
Actual results:
  I found redundant data to an extent I did not expect.

Expected results:
  I did not expect to see this level of redundancy.


Additional info:
   good folks reduced one duplication of kernel src with FC3
   and recent FC2 updates.   There is an opportunity to save
   bandwidth and disk space if the linux-2.6.9.tar.bz2
   file was packaged in something like kernel-base and distribute 
   the patches and spec/ build stuff in kernel-update

I suspect that any change to this has non trivial impact on the user
community so I do not wish to rush in....

I have no clear vision of a fix, I just wish to point out this
duplication of bits so a brighter mind than I has the chance to
inventing a way to tidy this up for FC4 or FC5....

Thanks,
mitch