[R] Unable to allocate arrays of size > 2GB in 64 bit Windows 7 R

[Bhattacharyya, Siddhartha]

I seem Unable to allocate arrays of size > around 2GB in 64 bit Windows 7
R. There is a lot of main memory available. The memory.limit is set to the
max memory available, and there is more than 10GB of that available when R
returns an 'unable to allocate memory' error.   Is this a limitation of R
even in 64 bit Windows 7?  Or is there a wY to get I've this?

Thanks.