zImage works, bzImage doesn't

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This was formerly titled:
	Out Of Memory, System Halted.
I am sending a copy to the maintainer of the bootdisk howto file,
in hopes he can help.
I read that page, and found nothing on this anomoly.

As you recall, I found that when I deleted a line of code,
a line that is never executed in the running kernel anyways,
it would boot up just fine, off of lilo,
off of my floppy disk.
When I put the line back in, the system said
"out of memory, system halted".
This was part of uncompressing the kernel;
it never even got to the first line of output that gives
the Linux version number and date/time of build etc.
So the problem couldn't be caused by my missing or added
line of code.
I repeated this several times: in = failure, out = bootup just fine.

At first I thought my line of code was
making the kernel just a tweek too big.
I mean, it said "out of memory", didn't it?
But I have successfully booted larger kernels,
and I was able to make the pathological kernel much smaller,
by stripping out other stuff, and still leaving my troublesome line of code in,
and it still wouldn't boot -- out of memory.

I then tried something else.
I made zImage, rather than bzImage.
Same system -- zImage works just fine, bzImage doesn't.
I have to assume that my line of code triggered an incompatibility
between the gzip compress utility that makes bzImage and the onboard uncompress
utility that expands it at boot time.
Something about my bit pattern, when compressed and uncompressed,
made the system look huge, rather than its actual 1 meg size.
I'd rather have this happen than an uncompression that "looks"
ok, but actually gets some of the bits wrong.

This is a serious problem, and I hope somebody can look into it.
I'll gladly make my vmlinuz, System.map, zImage, and bzImage available
to anyone who things they can track down the problem.
Meantime, for those of you fellow listers who are building
kernels, I'd recommend zImage rather than bzImage.
You may need to keep your kernel a little smaller,
but that's a small price to pay for some piece of mind.

Karl Dahlke

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