Re: VI reasons (was Re: Base Set: Suggested additions & removals.)
> Can someone give me a quick summary of bzImage vs zImage and why Debian
> needs to use bzImage on the root disks at all? Not only does it cause
> problems with some notebooks, it causes problems my desktop -- spontaneous
> reboots after "Uncompressing Linux...." sometimes.
Well. It goes like this.
When you boot the kernel it copies the Image from the disk to 0x1000
(about 64k). If the Image is beyond 600k then you have a problem because
it suddenly will not all fit in low memory.
A bzImage is more sinister. After it loads a few block in it makes some
bios calls to copy the blocks up to 1 meg where the 3rd stage boot loader
will run. After that it uncompresses the kernel to some location then
copies it to it's proper placement at 1M. a zImage simply uncompresses the
kernel to 1M.
In theory, on a notebook the int calls are glitchy and crash the system.
If your kernel is > 600k you MUST use a bzImage and you MUST load it into
memory above a meg (ie protected mode). zImages work until that limit is
reached.
I'm not sure how syslinux loads the ram disk, but I think it must load it
into high memory and it might use bios calls to do it.. It's also possible
that syslinux is unsing an incompatible way of fiddling into protected
mode that mucks things up, I've only looked at the kernel boot loader.
Jason
Who just today got a 200k 2.0.34 zImage kernel to boot off flash on an
embedded AMD 586 from Octagon
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