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| 4RING_OS ver. 0.00 https://forum.osdev.org/viewtopic.php?f=2&t=56053 |
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| Author: | Isa [ Mon Dec 20, 2021 6:43 am ] |
| Post subject: | 4RING_OS ver. 0.00 |
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 |
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| Author: | Octocontrabass [ Mon Dec 27, 2021 6:10 pm ] |
| Post subject: | Re: 4RING_OS ver. 0.00 |
Quote: 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. |
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| Author: | Isa [ Tue Dec 28, 2021 2:48 am ] |
| Post subject: | Re: 4RING_OS ver. 0.00 |
Octocontrabass wrote: Quote: 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. |
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| Author: | Isa [ Tue Dec 28, 2021 2:39 pm ] |
| Post subject: | Re: 4RING_OS ver. 0.00 |
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? |
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| Author: | Octocontrabass [ Tue Dec 28, 2021 3:58 pm ] |
| Post subject: | Re: 4RING_OS ver. 0.00 |
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.) |
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| Author: | Isa [ Wed Dec 29, 2021 2:27 am ] |
| Post subject: | Re: 4RING_OS ver. 0.00 |
Right, thank you! |
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