Begining of BareMetal

nekros · Post by **nekros** » Mon Mar 17, 2008 4:46 pm

This is the start of a design for my OS called BareMetal. It is FAR from complete as you can see, though I thought you might be interested in the proposed layout of the system.(aka. The Diagram)

Rename the extension to PDF.

Paw · Post by **Paw** » Mon Mar 17, 2008 5:22 pm

I see a contradiction between "A stable OS that won't crash" (impossible per se) and "All software will run in ring 0"

nekros · Post by **nekros** » Mon Mar 17, 2008 5:54 pm

as stable as possible in ring 0. The idea behind singularity I think.

nekros · Post by **nekros** » Mon Mar 17, 2008 6:19 pm

Rename to PDF

piranha · Post by **piranha** » Mon Mar 17, 2008 6:59 pm

Kind of like an exokernel?

Are you going to implement lots/some/none syscalls?

-JL

nekros · Post by **nekros** » Mon Mar 17, 2008 7:32 pm

As few as possible, though enough to allow the full power of the hardware to be used.

Dex · Post by **Dex** » Mon Mar 17, 2008 7:32 pm

Its sounds like a 64bit ver of DexOS, From the design so far.

nekros · Post by **nekros** » Mon Mar 17, 2008 7:47 pm

Wait for the next part in the design, slightly different.

xyzzy · Post by **xyzzy** » Tue Mar 18, 2008 10:50 am

nekros wrote:as stable as possible in ring 0. The idea behind singularity I think.

Have you actually read anything about how Singularity works?

cyr1x · Post by **cyr1x** » Tue Mar 18, 2008 12:59 pm

Singularity runs managed-applications, thus they can be verified and isolated easily (more or less). If you want unmanaged code this is nearly imposible.
Of course there're some exception like singletasking OS's (like the OS from Dex), which can crash too, but I think this isn't an option for you, is it?

Dex · Post by **Dex** » Tue Mar 18, 2008 1:27 pm

There's also console OS's like the xbox etc.

While the Xbox kernel is based on the NT/Windows 2000 kernel, it's extremely lean. There's no virtual memory paging, and only a single process is allowed (though that process can spawn multiple threads). The entire kernel fits into 150KB--far less than the 1MB original goal.
The development library is polling-based rather than event driven (unlike Windows). This was due directly to feedback from game developers.
The game owns the hardware--it runs in ring 0, and has direct access to all hardware (including CPU and graphics).
Memory allocation is the responsibility of the app--there's no front-end memory allocation.
While the APIs were familiar (Direct3D, DirectSound), the back ends were different, and highly tuned to the Xbox hardware. However, the input API is different from DirectInput on the PC.

nekros · Post by **nekros** » Tue Mar 18, 2008 2:39 pm

No preemptive multitasking, processes will give up the cpu when they get past their critical regions.

nekros · Post by **nekros** » Tue Mar 18, 2008 3:23 pm

Here is the new one, rename to .pdf as the extension.

Zenith · Post by **Zenith** » Tue Mar 18, 2008 4:43 pm

I'm just wondering - How would you force someone to develop their application to run in ring 3?

I mean, let's say you download something from a network, and you run it. According to what you've said, wouldn't that application get to decide which ring it's running on? Or is their some way the OS marks every 'trusted program'?

I think you're just dodging an issue here... Ring 0 vs. Ring 3 - Either developers will opt for the speed and freedom of ring 0 (very, very likely) or the restrictive 'stability' of ring 3 (unlikely). Just stick with one or the other!

Of course, all of this doesn't matter if you plan to be the only developer for your OS from now until forever.

nekros · Post by **nekros** » Tue Mar 18, 2008 6:02 pm

No, It doesn't matter if there is network services for ring 0. From a virus point of view the user can choose which one to use. I'd pick non-virus.