What is unreal mode ? (for the Glossary)

basically, unreal mode consist of breaking the '64Kb' limit of real mode segments, but still keeping 16 bits instruction and segment*16+offset address formation. You can find much more about it in OSRC

When should i use unreal mode ?

unreal mode is recommended in the two following cases :

  1. you're trying to extend a legacy 16-bits DOS program so that it can deal with larger datas and neither vm86, nor xms is suitable for your needs
  2. you're trying to load something that will run in 32 bits mode and which is larger than 640Kb (so you cannot load it in conventionnal memory) and you don't want to bother with a disk driver called from pmode yet, and you do not wish to switch between real and protected mode for copying chunks from the conventionnal memory buffer to the high memory areas ...

Of course, unreal mode is kinda useless as long as you don't have the A20Line enabled.

How do i set up unreal mode ?

See BabyStep7 :)

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