Re: boot sector f*ed

On Thu, 13 Aug 2009, PJ wrote:
Subject: Re: boot sector f*ed

Roland Smith wrote:
On Wed, Aug 12, 2009 at 03:54:31PM -0400, PJ wrote:

Well, I've been looking at the disk(s) and I have found some interesting
"shei**e" that doesn't make sense.
1. The fbsd minimal installation that I had set up for recovery of the
previous crash does not boot... Now, why in Hades is that? I hadn't
touched the disk since last using it to look at the corrupted disk
through an usb connection. The current crashed installetion was done
afterwards and the only change was in the bios to set the boot disk to
the new installation. The installation was finally completed with all
the programs working fine... and then BOOM!
2. I tried booting from all the disks on the machine (4 disks) and only
the current crashed one booted!... so, it's not the boot sector at
all... something is screwy on this machine; either the motherboard is
buggered (which I doubt, but not entirely), the disks are finished or
theres some kind of gremlin lurking in the confines of the box.


This sounds more and more like hardware troubles.

Indeed it does, more and more since.

A few things to check (in order of decreasing likelyness IMHO):
- Cables to the harddisks: Make sure they are properly connected. A machine of
mine suddenly started getting disk read errors after I put in another
graphics card. It turned out that the SATA connector to that drive had come
partially loose.
- Powersupply: check the voltages (preferably under load) with a monitoring
app like mbmon. If that's not possible, check in the BIOS. A failing
powersupply can give weird unreproducable errors. If you have ever heard a
popping noise from the machine it could be a short in the powersupply caused
by dust. I've seen that fry motherboards.
- PCI cards: check that they are seated properly. Although in this case I'd
say this seems the least likely.

I usually bet first on the power supply .. but it's not my money :)

I apologize for the lengthy explanation below, but perhaps it will give
some insight on what is see from this end:

Chomping heavily; some useful background but a bit much, no disrespect.

machine. The troubles began when I tried to install flashplayer on the
7.1 machine.

Or could be a hardware issue that became evident around the same time?

bash4 and fluxbox for X. Everything seemed to work fine. I ran all the
programs and saw that all the files I had recovered from the crash were
recovered and working. Man, was I ever happy!
I shut down for the night and looked forward to getting bask to normal
development of my current projects.
In the morning, I boot up and WHAM!... the system is f**cked. And so am I.

Have you tried swapping the power supply? I assume you've swapped the
cables, removed cleaned and replaced cards, checked CPU temperature etc?

Now, the problem is that it is imperative to be able to figure out what
exactly is going on. Well, the problem with that is that I do not seem
to be in a position to do what is required. For one thing, I do not know
how I can save testing output to an external file when I am working on a
temporary shell on the problem machine. Perhaps you could indicate what
I should be doing or where to look for information.

Steve Bertrand has most recently addressed those issues, good advice,
especially "don't panic" :)

Another problem is rather a strange quirk or I don't know what - The
problems I am having are on two very similar machines: 1 is a MSI 6758
875P NeoFisr motherboard running on a Pentium 3.0ghz CPU; the other is
the identical board with a Pentium 2.4ghz CPU. The strange thing is that
even with identical bios, the bios does not act the same on both
machines. The final install that was so promising was on the 2.4 ghz
machine. Except for being somewhat slower (I find it rather slow
compared to the the 3ghz, but maybe that's normal) it always worked
without problems.

Have you tried putting the HD from the problem 2.4GHz machine in the
3GHz box, to see if it behaves properly there? Have you tried running
various hardware diagnostic programs over the flakey box? Overnight
memtesting can reveal other problems even if memory is fine. There are
quite a few diagnostic CDs around; some boot some Linux, some DOS even,
it doesn't really matter if they can prove/disprove the hardware.

anyway - I tried booting a minimal installation on the 2.4ghz machine
from a disk that was set up before the crashed disk was installed and
that boot did not work... there was no reason for it to not work... all

Smells like flakey hardware .. intermittent, inexplicable glitches. It
might survive hours on one workload, minutes on another, no sense to it?

All that I am seeing is that there is either a problem with the bios
(which I even reinstalled and that changed nothing in the functioning)
or something is going on with the OS.

After you've thoroughly proven the hardware is AOK under sustained and
varied pressure, then you can suspect software issues - which tend to be
far more consistent and repeatable - but if the hardware's acting flakey
then you likely won't see any consistency in software issues, which does
seem to concur with your descriptions to date.

I must say, it is weird that with FBSD 7.2 things have not been going
well at all...

Well, since that particular point in time, at least?

So, now I am trying to set up 7.2 on this new disk and let's see what
happens.
I'm going to run some tests on those disks, including the one that maybe
is defective... I'll post results if possilbe.

I wouldn't even try doing anything with disks until positively ruling
out any hardware issues, given that at one stage you _apparently_ lost
the boot sector, and it or another possibly intermittent issue prevented
booting. You've since said that the 3GHz box with same BIOS boots up
'differently'. Has it always been so?

Sometimes, quite often in fact, I've found just disassembling, thorough
cleaning, fresh heatsink paste maybe, and reassembly solves many issues,
without ever knowing what exactly did the trick. Life's like that ..

HTH, Ian
_______________________________________________
freebsd-questions@xxxxxxxxxxx mailing list
http://lists.freebsd.org/mailman/listinfo/freebsd-questions
To unsubscribe, send any mail to "freebsd-questions-unsubscribe@xxxxxxxxxxx"

Relevant Pages

  • Re: boot sector f*ed
    ... "I updated the machine and it doesn't boot anymore". ... 875P NeoFisr motherboard running on a Pentium 3.0ghz CPU; ... Please capture the output from running fdisk and bsdlabel on the problem disk ... anyway - I tried booting a minimal installation on the 2.4ghz machine ...
    (freebsd-questions)
  • Re: unable to install XP on new HD
    ... connected to the primary master HD and I was once able to boot to OS XP ... the floppy ... For a boot disk go here: http://www.bootdisk.com/bootdisk.htm and use the ... files and so I have to abort installation. ...
    (microsoft.public.windowsxp.help_and_support)
  • Re: need to delete my pc, going to buy a new one and sell my old p
    ... All data on the disk should be ... how are you going to reinstall Windows XP? ... Without the installation media, all you have for sale is the hardware. ...
    (microsoft.public.windowsxp.general)
  • Re: how to boot or access problem file system
    ... Since the boot code cannot locate your kernel, ... fsck_ffs on your disk partitions. ... there so many problems being brought up on the mailing lists? ... of are those on the installation disks ... ...
    (freebsd-questions)
  • Re: Inaccessible_Boot_Device
    ... The "Inaccessible boot device" message occurs much later, ... Windows installation is ported to a different PC. ... Re-installing Windows is simple: Boot the machine with your Win2000 CD, ... allow the disk to be partitioned and formatted, ...
    (microsoft.public.win2000.general)