The problem with NFS Root is that i don't have a second machine :(. Anycase, it took a while and i got a uml to work on a debootstrap ubuntu edgy with network support and no super user for the helpers so i won't make a mistake (took half a day just for that). Got my hello world module though so that is something. Though there is an irritating thing with ubuntu where the 6 virtual consoles pop out to the desktop and cannot be closed. haven't figured out how to kill them yet. and that the console is not popping up on the shell where the uml loads. As for the performance, it loads pretty quick and i am not running servers here so it is ok for learning purposes.
The only problem i understand there is with UML is that you cannot work with real devices (since the kernel is talking to the host kernel. I imagine this is the same with vmware/etc emulation. On Tuesday 13 February 2007 20:02, Gilboa Davara wrote: > On Tue, 2007-02-13 at 18:54 +0200, Tzahi Fadida wrote: > > Hi, > > As you might guess from a previous thread, i am trying to learn modules > > development. I use kubuntu as my dist. > > My first goal is to be able to run the hello world module example in the > > linux device drivers 3rd edition book. > > Apparently in 2.6 you need to have the whole kernel compiled just to > > build one module, which is not a problem though i don't want to start > > spending days tuning it up to work correctly with my system. > > You don't. > You just need the skeleton kernel-devel package. (A cut down kernel > image that includes the kernel configuration, headers and kbuild > environment) > > > What should be my workspace so i can start learning: > > User mode linux? qemu? vmware? XEN :) ? > > In general, I use both VMWare server and an NFS-root-mounted machine. > Xen: At least in Fedora-land, it tends to be very sensitive to kernel > updates - a very frequent event. > QEMU: Too slow. (Even with now-GPL'ed kernel module.) > KVM: No hardware support. (Old[er] dual core Opterons @work/home) > UML: it has been a while since I used it - but even with the SKAS > host-patch, performance is less then staggering and it was -very- > sensitive to the base (read: un-patched) kernel versions. > > NFS-root: > The NFS-root is also an interesting option. (If you can spare a second > machine/SBC/embedded board) > A. You don't risk the host machine. (I did crash vmware/Xen a couple of > times - risking the integrity of the host machine) > B. The guest machine is booting from a network FS - no matter how > painful your crash is (Read: doing memset with a negative size) you > won't damage the guest OS image. > C. Super fast boot. My NFS test machine (with a modified stripped-down > Slackware) boot in less then 15 seconds. > > > P.s.: naturally i am impatient to start coding yesterday :) > > Yep... Debugging kernel OOPs is pure joy ;) > > - Gilboa > > > ================================================================= > To unsubscribe, send mail to [EMAIL PROTECTED] with > the word "unsubscribe" in the message body, e.g., run the command > echo unsubscribe | mail [EMAIL PROTECTED] ================================================================= To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
