Although the DOS operating system is not designed to take advantage of these features, some DOS programs can run in protected mode using special drivers. More sophisticated operating system, such as OS/2, Windows, or UNIX, have built-in support for protected mode.

Article on 386 Protected Mode
This August 1991 article provides information on 386 benefits, protected vs. real modes, protect mode addressing, and linkers.

DOS Protected Mode Interface (DPMI)
This is a programmer's reference copy of the DOS Protected Mode Interface, a protected mode API specification for DOS extended applications.

Protected Mode Basics
Provides a lengthy and detailed explanation of protected mode and how the CPU handles it internally, the role of memory management, and how to enter and exit protected mode.

Technote on CPU addressing modes
This page includes full descriptions of each CPU addressing mode, including protected mode, with a diagram of how it works.

Utilized Protected Mode features page
This page highlights the key advantages of using protected mode.

What impact does protected mode have on my code?
This page notes both the impact protected mode has on performance, and what influences the performance of protected mode programs.