John Baldwin wrote: >On Wednesday 01 February 2006 15:20, Julian Elischer wrote: > > >>John Baldwin wrote: >> >> >>>On Wednesday 01 February 2006 08:41, Oliver Fromme wrote: >>> >>> >>>>Julian Elischer wrote: >>>> >>>> >>>>>Oliver Fromme wrote: >>>>> >>>>> >>>>>>[...] >>>>>>I think the most visible changes in the boot blocks was >>>>>>UFS2 support and the removal of nextboot(8) support. >>>>>> >>>>>> >>>>>which I hope to put back because we continue to need it. >>>>> >>>>> >>>>I agree that it's needed. It's a very useful feature. >>>> >>>> >>>> >>>>>(The new nextboot being dependent on the root filesystem still being >>>>>ok which is unacceptable to most embedded devices I've worked on, and >>>>>why we still use the old bootblocks on all systems shipped.). >>>>> >>>>> >>>>> >>>>>From my point of view, the biggest problem with the old >>>> >>>>nextboot was the fact that it ignored loader(8) and tried >>>>to load the kernel directly. While that might work under >>>>certain conditions, it's not good in general. >>>> >>>>Therefore I think that a new nextboot implementation >>>>should be implemented in loader itself. Since loader(8) >>>>doesn't (and shouldn't) support writing to UFS2, the >>>>state information should be written to an unused area in >>>>block 2 on the disk, or something similar. In fact, one >>>>byte is sufficient: It can be used as an index into a >>>>table (ASCII text file), e.g. /boot/nextboot.conf. >>>> >>>>Would that be feasible to implement? >>>> >>>> >>>/boot/loader already does nextboot and does it by using UFS writing (which >>>it does implement and use on archs whose disk drivers support writing >>>such as i386) to overwrite (but not extend) /boot/nextboot.conf. >>> >>> >>which is exactly the feature that I wanted to avoid with the original >>nextboot(8). >>Do NOT get any where-to-boot-from info from the possibly suspect >>filesystem. Do NOT write back to the "possibly-suspect-filesystem". >> >>The original nextboot was BIOS specific and not portable which is why >>the new one >>has some good points (portable), but it didn't rely on correctness of the >>bootblock FS code or an intact first FS. >> >> > >You are already presuming something of an FS as that is where you get your >loader and kernel from. (Well, you could get the kernel from somewhere else >perhaps, but not the loader unless you are using PXE or a CD to boot.) > > I'm not presuming anything about a particular slice, if I can specify another one..Received on Thu Feb 02 2006 - 18:10:21 UTC
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