The following provides a general description of the different forms of memory available in the MS-DOS environment on PC and PS/2 systems. It also discusses what kinds of software use these different areas, and what drivers are needed to create and control some of these areas.

The diagram below shows a memory map that outlines the layout of these different forms of memory. There are many forms of memory: conventional, extended, EMS, XMA, and XMS. Below is a description of each form of memory, and how they relate; because there are many relationships, you may have to read the following material twice to eliminate any references to undefined terms.
The following is an illustration that shows the various components of memory that are available (please note that it is a very general map).

* nM = 16 MB on an 80286, 4 gigabytes on an 80386

• Types of Memory - discusses the major forms of memory, and their physical and logical components and drivers.
• Equations - gives some handy equations for showing how these areas of memory can be used or emulated.
• Memory Drivers - gives a brief description of the memory management device drivers mentioned in this article.