title: ffsave from ff package creates a large file "clone.ff"
body: <p>I have a question about ffsave(from ff package).</p>
  
  <p>I have a large matrix that I save like this:</p>
  
  <pre><code>ffsave(Mat, file=paste(results_wd,"Mat",sep=""), rootpath=results_wd)
  rm(Mat)
  gc()
  </code></pre>
  
  <p>In my folder (results_wd) I have "Mat.ffData", "Mat.RData" and "clone28b4d345101.ff"</p>
  
  <p>And when I load my matrix:</p>
  
  <pre><code>ffload(paste(results_wd,"Mat",sep=""))
  opening ff /home/usr/Docs/Data/Analogs/Simul_arch_19582008/Precip/clone28b4d345101.ff
  Warning:
  In FUN("clone28b4d345101.ff"[[1L]], ...) :
  NOTE: did not overwrite file 'clone2f3d73a2e574.ff'
  </code></pre>
  
  <p>So it loads data from clone28b4d345101.ff</p>
  
  <p>The problem is that clone28b4d345101.ff size is 10Mo and I have 608*5 files like this so using ff is useless... Even if I close R, the files are still here (I thought it was something load with the workspace). When I delete these files, they come back when I use ffload.</p>
  
  <p>Can't I use ffsave withouh having a file named clone(numbers).ff (just with name.ffData and name.RData)?</p>