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After learning a lot, I have decided to make my os in unreal mode. I will not use PM because I do not want to spend all that time writing new bios interrupts, drivers, etc for PM. It will be a simple OS with interrupt based multitasking. Each program will be run in a virtual page(setup by the kernel). When it needs to switch a task, the kernel will setup the page. The problem with unreal mode, is code needs to be under 1 mb. So the virtual paging system will swap the program into memory above 1mb(code), then bring in code in from another process above 1mb. All data will be above 1mb, as not to take up code space(the stack will also be below 1mb). It wont need to resort to this swapping system unless there is too much code to be held below 1mb. It will also have a feature that allows a process that needs maximum performance to stop task switching.

the way you have described it, it is not possible. unreal mode does not provide the features you say you are going to use.

which features are those? I will simulate paging in the kernel(I figured out a way to do this). It is unreal mode so I can get above 1 meg. What other features wont work?

Hi,
those are good ideas and they seem possible. the only way to find out what will work and not is to implement the ideas!

I think PMode is easier than having to do all that re-programming. (And PMode-designed OS is faster than real-mode. You can use v86 to use the BIOS in PMode....Tim Rob knows v86..).

PMode lets you do alot more protection stuff....but it's your OS ;D

doesnt v86 run in rung3? I sorta need 0 for my OS.

I agree with Tom: using anything other that protected mode will be more trouble in the end.

neowert: yes, V86 code does run in ring 3, but all that means is that it can't screw up any of the ring 0 stuff. You could still grant it access to I/O ports and selected memory regions. Failing that, you could trap any illegal port or memory accesses and handle them in kernel mode.