I'd like to understand what's being described in this article, but unfortunately I lack the necessary educational background. Does anyone have any links to other resources that will allow me to better understand what is being discussed in this post?
Virtual memory is part of the fields of computer architecture and operating systems; popular textbooks are Computer Architecture: A Quantitative Approach and Modern Operating Systems.
CPUs prior to 386 had direct access to physical memory. From 386 on, you could enable protected mode (default for Linux and Windows 95+) in which a pointer doesn't point to a physical location but to a virtual address that system translates to physical memory or disk-cached memory. That's the most basic fact. With much luck, that's the only thing you need to know to understand it :-)
This article is already a very high level description of Linux memory management (specifically on 32 bit Intel processors). If you want to move down to lower levels of abstraction and learn more details, then keep reading that blog! On the other hand, if you want a less technical description of these concepts then I'm not sure where to look.