| Bill Jonas on Tue, 19 Mar 2002 13:51:52 -0500 |
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On Mon, Mar 18, 2002 at 11:24:12PM -0500, Michael Leone wrote: > /dev/rootpartition? never saw that one before. A symlink called > /dev/root, pointing to the real root partition. I meant it symbolically; I implied a '$' before "rootpartition", or "replace 'rootpartition' with your actual root partition name (hda5, hdf1, sdb2, etc)". > Insufficient in what way? HURD is a microkernel, and it uses servers to do nearly all the work of a proper kernel. It only coordinates the servers and passes messages between them. For example, a server allows you to use your ethernet card, and a server provides a login prompt[1] (instead of using a getty). Additionally, unlike a monolithic kernel like Linux[2], there's no "filesystem code" in the kernel itself; it's handled by a server, too, and that server needs to be started in order to be able to access the filesystem. This is done in GRUB with the "module" directive after you specify the root filesystem (with "root (hdX,Y)", X and Y being the disk and partition numbers, respectively) and the kernel image (which, in the case of Debian GNU/HURD, would be "kernel /boot/gnumach.gz"). More information is available at <http://web.walfield.org/papers/hurd-installation-guide/english/hurd-install-guide.html>. I'm not aware of any LILO equivalent to GRUB's "module" directive. (See also <http://www.debian.org/ports/hurd/> and <http://www.gnu.org/software/hurd/>. If anyone decides to give it a spin, note that you'll need the dummy packages from <ftp://alpha.gnu.org/gnu/hurd/debian/dists/unstable/main/binary-hurd-i386/dummy/> in order to satisfy dependencies in the ported Debian packages before you can start installing stuff with apt.) [1]Because of the architecture of the HURD, the traditional limitation that a process can only reduce its privileges no longer applies. Assuming a process has permission somehow, it can actually *increase* its privileges. This leads to very interesting possibilities. One of the first such things that I noticed was that instead of a getty, you basically get a bash prompt when you boot the system. (I'm assuming it's started by a Mach server.) This shell has zero privileges (think user "nobody"), but you can still look around the system at whatever is allowed for all to see. When you authenticate using "login $USER", you inherit the process (like a getty) and your privileges get elevated to that of the user as which you logged in (unlike a getty, where it drops root and goes to your username). [2]Yes, Linux is modular now, but when you load a module, the kernel and the just-loaded module act as one unit. -- Bill Jonas * bill@billjonas.com * http://www.billjonas.com/ Developer/SysAdmin for hire! See http://www.billjonas.com/resume.html Attachment:
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