Hi all, I am running bioconductor on a MAC OS 10.4.1 and have been unsuccessfully trying to get Crispin Miller's justMAS function in the simpleaffy to work for a while, and I think I've just been able to get it to work reasonably well, so if anybody else is trying to run this function on a mac, I may be able to spare you a headache. Basically, what I did was download the source package from the bioconductor website, compile simpleaffy.c and justMAS.R files separately on the X11 terminal, and then modify the justMAS.R file a bit, substituting an expresso background correction call in the place of the c implementation of the background correction. -Eitan