[PLUG] Troubleshooting hardware

[drew wymore]

On 5/2/07, John Jason Jordan <johnxj at comcast.net> wrote:
>
> On Tue, 1 May 2007 20:14:58 -0700
> "Quentin Hartman" <qhartman at gmail.com> dijo:
>
> > Try doing some other I/O intensive thing, like "cat /dev/zero >
> zeroes.dat"
> > or something similar to workout the HDD. Perhaps it is a heat issue, but
> > it's not in the CPU, but rather the drive controller on the
> Southbridge...
> >
> > Download the Ultimate Boot CD and run MHDD on the drives (hard disk
> tools,
> > 4th or 5th page, item F5. Once in MHDD, select your drive and hit F4 to
> > bring up the scan option window and then hit F4 again to start it) as
> that
> > will certainly work them out in a way completely isolated from your
> > potentially questionsable system image.
>
> First I downloaded the UCBD and used it to run the Western Digital
> Lifesaver Diagnostic tool on each of the hard disks. It ran for 75
> minutes each time with the hard drive light on solid the whole time. No
> errors on either disk. Then I ran memtest86 for an hour, and no
> problems.
>
> I discovered something while booting the UCBD -- at the start it
> presents a simple little word "boot" on the screen and if you don't hit
> Enter fast enough it will continue and boot from the hard disk instead
> of the CD. One time I was not fast enough and it booted from the hard
> disk. The interesting thing is that if I just boot without the CD I get
> to the point where it says "GRUB" and then hangs. But if the UCBD
> starts first and then it goes to the hard disk, Feisty actually starts
> to boot. It crashes to a command line, but the kernel loads.
>
> I figured that meant that maybe there was something in menu.lst that I
> could fix. However, I have a dozen or more live CDs of various flavors
> and only two will show the md devices when I run cat /proc/dev. One is
> GRML Rescue CD and the other is Aaron's rescue CD. Aaron's won't
> mount /dev/md1, but the GRML Rescue CD will. However, it does something
> weird that I have not figured out. I mounted /dev/md1 at /mnt/md1. When
> I do "nano /mnt/md1/boot/grub/menu.lst" I get a menu.lst file, but it
> is GRML's menu.lst -- it's definitely not mine. Yet navigating around
> in /mnt/md1/ all the rest is mine, that is, it finds /home/jjj and all
> the files in it are mine. Weird.
>
> So I started downloading a bunch of other rescue CDs. So far none of
> them can see /dev/md*. While doing the downloading I tried
> "cat /dev/zero > zeroes.dat" and it powered off the computer after a
> couple of minutes. I read what little there is in man cat, but couldn't
> figure out what exactly this command does. What does it mean that it
> caused a shutdown?



cat just reads the contents of a file and outputs it to the terminal. tac
does the same thing but starts from the bottom of a file whereas cat starts
from the top of the file. It shouldn't have caused a shutdown, sounds like a
dodgy power supply to me.