2012/11/1 Mulyadi Santosa <mulyadi.santosa@gmail.com>
Hi..
On Wed, Oct 31, 2012 at 9:30 PM, Fan Yang <lljyangfan@gmail.com> wrote:
Hi all: I have a problem, if i don't active the page mechanism just use the segment mechanism at the x86 cpu, how can I manage the Multi-tasking?
multitasking and memory management are not directly related IMHO, but you're right that we need process address space switching.
I think what you're going to do is already done by Linux kernel port to non MMU architectures. Can't recall which ones, so try to check https://en.wikipedia.org/wiki/Memory_management_unit for further examples
- regards,
Mulyadi Santosa Freelance Linux trainer and consultant
blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com
Hi Mulyadi Santosa Very honored to see your reply.Yes, the page mechanism can protect different task to interfere each other by mapping different task to different physical memory, and this work is already done by kernel. In order to solve the prev problem I look through the intel manual http://download.intel.com/design/processor/manuals/253668.pdf ,and in chapter 3.1 I see this sentence "Segmentation provides a mechanism of isolating individual code, data, and stack modules so that multiple programs (or tasks) can run on the same processor without interfering with one another." then this manual tell me that "There is no mode bit to disable segmentation. The use of paging, however, is optional." that is to say the segment mechanism must be support in the OS, but the page mechanism is optional, but at the manual I can't find any example to explain how to use the single segment mechanism to protect the different tasks to interfere with one another ,so I have a guess you just see. BTW, I try the 2.6.32.27 kernel version but nothing changed. Thanks Fan