[R] Problems saving ff objects

[Jannis]

Dear list,


I am trying to understand and use the ff package. As I had some problems saving some ff objects, and as I did not fully manage to understand the whole concept of *.ff, *.ffData and *.RData with the help of the documentation, I tried to reproduce the examples from the help of ffsave.

When I ran, however : (copied from the help)

 message("let's create some ff objects")
  n <- 8e3
  a <- ff(sample(n, n, TRUE), vmode="integer", length=n, filename="d:/tmp/a.ff")
  b <- ff(sample(255, n, TRUE), vmode="ubyte", length=n, filename="d:/tmp/b.ff")
  x <- ff(sample(255, n, TRUE), vmode="ubyte", length=n, filename="d:/tmp/x.ff")
  y <- ff(sample(255, n, TRUE), vmode="ubyte", length=n, filename="d:/tmp/y.ff")
  z <- ff(sample(255, n, TRUE), vmode="ubyte", length=n, filename="d:/tmp/z.ff")
  df <- ffdf(x=x, y=y, z=z)
  rm(x,y,z)

  message("save all of them")
  ffsave.image("d:/tmp/x")

I get:

Error in ffsave(list = ls(envir = .GlobalEnv, all.names = TRUE), file = outfile,  : 
  the previous files do not match the rootpath (case sensitive)


Whats wrong here? Should this not be working as I did not change anything in the code?



Cheers
Jannis


> sessionInfo()
R version 2.12.0 (2010-10-15)
Platform: i386-pc-mingw32/i386 (32-bit)

locale:
[1] LC_COLLATE=English_United States.1252 
[2] LC_CTYPE=English_United States.1252   
[3] LC_MONETARY=English_United States.1252
[4] LC_NUMERIC=C                          
[5] LC_TIME=English_United States.1252    

attached base packages:
[1] tools     stats     graphics  grDevices utils     datasets  methods  
[8] base     

other attached packages:
[1] ff_2.2-2   bit_1.1-7  rj_0.5.2-1

loaded via a namespace (and not attached):
[1] rJava_0.8-8