On Fri, Mar 14, 2008 at 12:03:40PM -0400, Douglas A. Tutty wrote: > On Thu, Mar 13, 2008 at 10:19:09PM +0000, [EMAIL PROTECTED] wrote: > > On Sat, Oct 27, 2007 at 05:30:49PM +0100, Digby Tarvin wrote: > > > I have now had time to get back to investigating this, and after a > > systematic test of all the differences between the 486 config and > > the unstable 686 config, I have discovered that the critical item > > was the setting for High Memory Support. In the 486 Kernel this > > is set to 'off', and for the 686 kernel it is set to '4GB'. > > > > Having identified that this setting determines if my kernel will be > > stable or not, I then tried booting the default (686) kernel with > > the boot option 'mem=896M' (foregoing the top 128MB or ram) > > > > Sure enough, the full pentium Debian kernel is now stable! > > > > Still trying to find a way to determine if this indicates a fault > > in this machine, or some subtle compatability issue with it. > > > > If anyone has any idea what might be causing this particular fault I > > would be most intetested to hear. I would have thought some bad ram > > would have been detected by the BIOS or the install disk memory tests. > > And I am told that the Windows system which it came with runs without > > any problem. I wonder if there is anything about the way HIGHMEM is > > used that would show up some subtle flaw in this machine? > > What happens if you swap memory around in the box. If it causes errors > on your previously-stable kernel, then that's a sign. What happens if > you install memtest+ which puts a line in grub's menulist so that you > can boot into pure memtest and let it cook for a couple of days?
I did try the memory test from the install disc back when I fist started, although can't remember if I used the debian or the ubuntu disc. Anyway, it failed to find anything wrong. I assume that would be the same as memtest+ wouldn't it? Good idea on swapping the memory around. I'll give it a try. I may have spoken too soon about the mem= argument though. It certainly allowed HIGHMEM enable kernel to boot all the way to X (which it never does otherwise), but I still had my kernel build fall over after a couple of hours with a bus error. I have just re-built the standard 686 kernel with HIGHMEM off to confirm that that gets me back to complete stability. I am tempted to adjust my memory boundaries so that I can use the full 1GB of ram without having HIGHMEM enabled (ie change the 3G/1G split to a 2.75G/1.25G split). That would give me access to all the resources - but it would be more satisfying to know exactly what the issue is.. Regards, DigbyT -- Digby R. S. Tarvin digbyt(at)digbyt.com http://www.digbyt.com -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
