hi, Sticking to intel architecture, you will see the intel manuals but not repeating the things, what they says that level 0 is highest privilage level and code running in level0 can access any other code but vice-versa ofcourse not allowed, every OS takes the benifit from that, to separate the kernel code and data segments which executes in higher privilage level from user code and data segments which executes in ring3, this way programs runnning with kernel privilage level actually called to be executing in kernel space and others in user space, when one make a system call , the switch from user space to kernel space happens it is nothing but the segment selectors are loaded with kernel code and data segments, the arguments etc. are passed in registers, and then after call is over , again segment selectors are loaded with user code and data segment(although scheduler is called in between when return from sysctem call). Prasanna. --- kleber@katatudo.com.br wrote: > What is kernel space e user space ? > > > ---------------------------------------------------------------------------------- > KATATUDO sua melhor pesquisa na internet. > Primeiro WEBMAIL gratuito com espaço ILIMITADO > Sistema Desenvolvido 100% com Software Livre > http://www.katatudo.com.br > > -- > Kernelnewbies: Help each other learn about the Linux > kernel. > Archive: > http://mail.nl.linux.org/kernelnewbies/ > FAQ: http://kernelnewbies.org/faq/ > > __________________________________ Do you Yahoo!? Yahoo! Mail - You care about security. So do we. http://promotions.yahoo.com/new_mail -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
