Bug#485790: generate separate /boot as workaround for buggy LBA48 ?
Robert Millan <rmh@aybabtu.com> writes:
> On Thu, Jun 12, 2008 at 12:58:13PM +0200, Frans Pop wrote:
>> On Wednesday 11 June 2008, Robert Millan wrote:
>> > This is not a bug about a problem I found, but about a problem I think
>> > can become common with the introduction of >2 TiB disks.
>> >
>> > A while ago, I found that bochsbios (the free BIOS used by bochs and
>> > qemu) had an incomplete implementation of LBA48 that caused a fatal
>> > error when attempting to access a disk sector above 2^32:
>>
>> There is also the (already current and somewhat common, see e.g. #481169)
>> issue described here:
>> http://wiki.linuxquestions.org/wiki/GRUB#Error_18
>
> Earlier instances of the same problem. The 8 GiB barrier was because of
> the BIOS only issuing one 24-bit ATA command. I'm not sure how common will
> the new limit be in comparison.
As well as 518MB, 2GiB, 32GiB, 64GiB, 128GiB. PC BIOSes are just
riddled with those stupid problems.
>> I wonder what we should do about this:
>> - just always create a /boot partition when guided partitioning is used
There is only one reason to have a seperate /boot: / is crypted. And
then you always need one.
In all other cases a small / partition is the superior solution imho.
So my solution would be to default to a seperate small / partition at
the start of the disk unless crypted is selected and then start with a
small /boot.
>> - add some special cases, but how to reliably detect them?
>> - always ask if a separate /boot should be created (or probably better:
>> create separate recipes for that)
>> - only document the issues and how to solve them manually
>
> The problem with attempting to detect this bug, is that there's a chance our
> probe causes the BIOS to crash, or abort with fatal error. I think this would
> outweight the benefit.
The risk of detection problems certainly outweighs the drawbacks of
always having a small / or /boot.
MfG
Goswin
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