[BioC] normalize chips from different expressets

[Matthew Hannah]

Rani,
If you want the standard rma normalisation then you could try 
eset <- rma(data)
or
justRMA()
which I think use less memory than expresso so you might be able
to do them all at once. Alternatively perhaps RMAexpress for
windows, this seems to perform well on 256RAM with c.25chips.

http://www.stat.berkeley.edu/~bolstad/RMAExpress/RMAExpress.html

Hope this is useful.
Matt