A faster connection between the computer doing the processing and a hard drive is the simple* way to increase the input/output speed. You could improve the connection or install R on a closer computer. If it's a database server, do the heavy work in the database (which can be safely assumed as very close to the data).
* If only it were simple
If possible, consider compressing data into
.gz files before moving them to the external drive. That way, there's less data to transfer back and forth. R has functions for doing this:
Differences between RAM and storage memory in where they're physically located and what they do:
Both RAM and hard drive memory are referred to as memory, which often causes confusion.
RAM stands for Random Access Memory. Physically, it is a series of chips in your computer. When your computer is turned on, it loads data into RAM . Programs that are currently running, and open files, are stored in RAM ; anything you are using is running in RAM somewhere...
When you save a document it goes on a hard drive, or another type of media storage device. Typically, this type of storage is magnetic, and does not depend on electricity to remember what is written on it. However, it's much slower than RAM .