[R] Pass By Value Questions

[lists at jdadesign.net]

I understand R is a "Pass-By-Value" language. I have a few practical
questions, however.

I'm dealing with a "large" dataset (~1GB) and so my understanding of the
nuances of memory usage in R is becoming important.

In an example such as:
> d <- read.csv("file.csv");
> n <- apply(d, 1, sum);
must "d" be copied to another location in memory in order to be used by
apply? In general, is copying only done when a variable is updated within
a function?

Would the following example be any different in terms of memory usage?
> d <- read.csv("file.csv");
> n <- apply(d[,2:10], 1, sum);
or can R reference the original "d" object since no changes to the object
are being made?

I'm familiar with FF and BigMemory, but are there any packages/tricks
which allow for passing such objects by reference without having to code
in C?

Regards,
Jeff Allen