4RING_OS ver. 0.00

This forums is for OS project announcements including project openings, new releases, update notices, test requests, and job openings (both paying and volunteer).
Post Reply
Isa
Posts: 4
Joined: Fri Dec 17, 2021 10:57 am
Libera.chat IRC: Isa

4RING_OS ver. 0.00

Post by Isa »

An experimental attempt to engage all 4 protection rings on Intel processors.

Source: https://github.com/isoux/4RING_OS
Blog: https://www.isoux.org/blog/article2/4ring_os
Octocontrabass
Member
Member
Posts: 5568
Joined: Mon Mar 25, 2013 7:01 pm

Re: 4RING_OS ver. 0.00

Post by Octocontrabass »

This is a fact that Intel's technical manuals emphasize from the first editions for i386: "call gates are much more versatile and faster than trap gates ..."
More versatile? Maybe. Faster? Depends on what you're doing.

Do you happen to have a floppy disk image? It's not easy to boot a CD on a 386.
Isa
Posts: 4
Joined: Fri Dec 17, 2021 10:57 am
Libera.chat IRC: Isa

Re: 4RING_OS ver. 0.00

Post by Isa »

Octocontrabass wrote:
Do you happen to have a floppy disk image? It's not easy to boot a CD on a 386.
On the GitHub I have a branch i386.
At folder tools/GRUB1/ is a compressed image without modules but HOWTO talks about how to do it.

This branch is dedicated to prerelease i386 and images and iso are compiled for 2Mb of memory.
I can compile release 0.00 for i386 if you want to just tell me how much memory you have because it's hardcoded for now?

I added a compiled floppy image for the i486 with 8Mb of memory.
Isa
Posts: 4
Joined: Fri Dec 17, 2021 10:57 am
Libera.chat IRC: Isa

Re: 4RING_OS ver. 0.00

Post by Isa »

Octocontrabass wrote:More versatile? Maybe. Faster? Depends on what you're doing.
Thanks for a very useful article!
When I said that call gates are faster, I meant that they are faster than interrupt traps, as the article showed. Too bad that sysenter or syscall can't call from other rings otherwise I would use them on newer processors.
As the article also said, I can't help but wonder why Linux still uses the slowest trap gates on the latest 64-bit machines?
Octocontrabass
Member
Member
Posts: 5568
Joined: Mon Mar 25, 2013 7:01 pm

Re: 4RING_OS ver. 0.00

Post by Octocontrabass »

Isa wrote:As the article also said, I can't help but wonder why Linux still uses the slowest trap gates on the latest 64-bit machines?
If you're talking about the INT 0x80 trap gate, it's for compatibility with 32-bit programs, it only supports the 32-bit system call numbers, and it only works on kernels that support 32-bit programs. 64-bit programs exclusively use SYSCALL. (And if you run a 32-bit program on the latest 64-bit machines, it will probably use SYSCALL or SYSENTER instead of INT 0x80.)
Isa
Posts: 4
Joined: Fri Dec 17, 2021 10:57 am
Libera.chat IRC: Isa

Re: 4RING_OS ver. 0.00

Post by Isa »

Right, thank you!
Post Reply