## 4.4 Operating systems: 32-bit or 64-bit

When we suggest that you should just buy more RAM, this assumes that you are using a $$64$$-bit operating system. A $$32$$-bit machine can access at most only $$4$$GB of RAM. Although some CPUs offer solutions to this limitation, if you are running a $$32$$-bit operating system, then R is limited to around $$3$$GB RAM. If you are running a $$64$$-bit operating system, but only a $$32$$-bit version of R, then you have access to slightly more memory (but not much). Modern systems should run a $$64$$-bit operating system, with a $$64$$-bit version of R. Your memory limit is now measured as $$8$$ terabytes for Windows machines and $$128$$TB for Unix-based OSs.

To find precise details consult the R help pages help("Memory-limits") and help("Memory").

### 4.4.1 Exercises

These exercises aim to condense the previous section into the key points.

1. Are you using a $$32$$-bit or $$64$$-bit operating system?
2. Are you using $$32$$-bit or $$64$$-bit version of R?
3. What are the results of running the command memory.limit()?