[R-sig-Debian] multiple versions on ubuntu

[Jeff]

I am new to ubuntu, but have used R for years on Fedora. I have a simple 
question that I do not quite understand. I first installed R from the 
ubuntu repository (2.6.2 I believe it was--whatever is current there) 
before finding the debian/ubuntu SIG here when searching for R 2.7.1. 
Subsequently I upgraded to 2.7.1 using the instructions at 
http://cran.r-project.org/bin/linux/ubuntu/. I am using Hardy on an 
amd64 platform. I did both installations with synaptic.

The question I have is why I end up with what appears to be two 
installation of R? I first noticed this when I looked at the package 
list and there were two sets of documentation for all of the packages; 
i.e., in /usr/lib/R/library and /usr/lib64/R/library. Checking these 
directories on disk shows what appears to be full mirror installations. 
In addition, running the little script to check for multiple packages at 
the R wiki for debian returns...

 Warning: you have multiple copies of the following packages:
           Package      LibPath                Version 
base       "base"       "/usr/lib/R/library"   "2.7.1" 
base       "base"       "/usr/lib64/R/library" "2.7.1" 
boot       "boot"       "/usr/lib/R/library"   "1.2-33"
boot       "boot"       "/usr/lib64/R/library" "1.2-33"
... etc.

At first I thought that synaptic had left the earlier version on, but 
this obviously shows that there are two sets of the same packages. This 
does not happen on my fedora 64 installation. Also, FWIW...

 R.version
               _                          
platform       x86_64-pc-linux-gnu        
arch           x86_64                      
os             linux-gnu                  
system         x86_64, linux-gnu          
status                                    
major          2                          
minor          7.1                        
year           2008                       
month          06                         
day            23                         
svn rev        45970                      
language       R                          
version.string R version 2.7.1 (2008-06-23)

Any thoughts?

Many thanks, sorry for such a simple question. I admit to being on the 
learning curve for unbuntu, and am more used to fedora/yum for 
installations.

Sincerely,

Jeff Gove