You don't have to specify the download type, as reposTools will figure it out for you. The difference is what operating system you are using. Since you are on windows, you got a win32 package, which was the correct result. Jim James W. MacDonald Affymetrix and cDNA Microarray Core University of Michigan Cancer Center 1500 E. Medical Center Drive 7410 CCGC Ann Arbor MI 48109 734-647-5623 >>> Willy Wynant <willy.wynant@curie.fr> 03/24/04 10:36AM >>> Hi, I am trying to understand the affy package and more specially the rma function. I type : > data<-ReadAffy() > toto<-rma(data,subset=NULL,verbose=TRUE,destructive=TRUE,normalize=TRU E,backgrounbackground=TRUE,bgversion=1) and I've got as result : Note: You did not specify a download type. Using a default value of: Win32 This will be fine for almost all users [1] "Attempting to download mgu74av2cdf from http://www.bioconductor.org/data/cdfenvs/repos/" [1] "Download complete." [1] "Installing mgu74av2cdf" Note: Running R version 1.8.1 and package mgu74av2cdf was built for R version 1.8.0 , installing anyway. [1] "Installation complete" Background correcting Normalizing Calculating Expression How should I decide which download type I have to specify? What are the differences between all of these "cdf-types" ? Could you help me? Thank you. _______________________________________________ Bioconductor mailing list Bioconductor@stat.math.ethz.ch https://www.stat.math.ethz.ch/mailman/listinfo/bioconductor