Question

What is flat mode memory, and what are the differences between flat mode and real/protected modes?

Answer 1

I hope this question is realted to the domain of computer architures and organization.

What is flat mode memory,

The flat mode memory id also know as linear memory model and it was mainly used in old computer architectures. It refers to a memory addressing paradigm in which the memory appears to the program as a single contiguous address space. The CPU can directly (and linearly) address all of the available memory locations without having to resort to any sort of memory segmentation or paging schemes. This helps the CPU to access the memory faster, But the limiation is that we cannot have many memory in such architecture.

The flat mode memory is most used in a simple controller, or in a single tasking embedded application, where memory management is not needed nor desirable, because it provides the simplest interface from the programmer's point of view, with direct access to all memory locations and minimum design complexity.

Differences between flat mode and real/protected mode

If you are asking about the difference between flat mode and realmode or protexted mode,

We can see two main difference

• Flat mode	Realmode/ protected mode
  memory reference is continious	the memory addressing may not be contiouns.
  Ability of multitasking is less	Can do multitasking better than the flat mode
  Used mainly for single task application computers or embended devices	Mainly used for multitasking architectures