DOS applications running native (not under Windows) run in Real Mode. See Protected Mode and Virtual 8086 Mode. THIS DEFINITION IS FOR PERSONAL USE ONLY. All other reproduction requires permission.

which is limited to 1MB of memory. See Real Mode. THIS DEFINITION IS FOR PERSONAL USE ONLY. All other reproduction requires permission.

Running a debugger like gdb with real-mode 16-bit code on the x86 platform is not the easiest thing to do, but incredibly useful when it comes to analyzing BIOS firmware and DOS software.

Where protected mode is convenient compared to real mode is that with the former the memory accesses go via the MMU and thus allows for access to 16 MB on the 80286 and 4 GB on the 80386.