Rik van Riel wrote: > On Thu, 25 Oct 2001, Patrick Ouellet wrote: > > > As a follower of linux for a couple of years now > > I wanted to go deeper into the madness, > > so I said to myself, why no go as deep as you > > can and get yourself into the Kernel. > > > > My simple question is this: > > > > Were should I start. > > A good place to start would be http://kernelnewbies.org/ > and also the kernelnewbies mailing list and IRC channel. > > > I would like to have a nice overview of the kernel > > something that would help me understand all the part > > of the kernel and how they work toghether. > > The book "Understanding the Linux Kernel" by O'Reilly > is nice, also see http://kernelnewbies.org/books.php3 > > regards, > > Rik Rik, I have basic questions regarding virtual address space and memory management, wondering you can give a help. 1. When userland process is created, how big the size of virtual address space the kernel assign to it, 4GB or it depends on size of the executable code? If 4GB is used, why is that because 3GB of it will be used excessively for the process and it is huge for most of programs. 2. Upon the creation of a userland process, a Page Table and a Page Directory will be created in main memory and stay there until the process is terminated. Besides that the /proc will have corresponding subdirectory for the process. Does the virtual address space has a copy of executable code on the secondary memory, usually on hard disk, or it just contains tables which holds addresses of executable code? Having a copy of every executable code on hard disk could take a lot of space if 3GB is used for each. 3. If I have enough main memory, I notice that the size of swap (maximum is 128 MB) always zero. Does that means no virtual address space on hard disk? 4. In Windows 98/ME, upon the termination of a userland process, this portion of occupied main memory doesn't get released, instead the main memory still hold contents of processes until page fault handler forces it out. Does Linux kernel use similar approach. If so, how these contents of processes in main memory can be reused assume same program starts to run again as the Page Table and Page Directory are gone? 5. In your 'Memory Management Talk', you mentioned the main memory is very slow. As speed of Intel processor grows rapidly, speed difference between cpu and main memory is getting big and bigger. How the issue could be solved in future? Does RAM reached its limitation of speed theoretically or L2 cache reached its limitation in terms of cost and size? Maybe I confuse some concepts here. Thanks you for the help, -Hong honghsu@bellatlantic.net - Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ IRC Channel: irc.openprojects.net / #kernelnewbies Web Page: http://www.kernelnewbies.org/
