Live knoppix goes wrong and becomes unusable. How can I fix it?

[winger9]

Summary:

1. I have a live knoppix DVD (see bottom of summary for version). Sometimes,
after booting the DVD, the system goes wrong and becomes unusable.

When this happened recently, the resulting effects were as follows:

a) When I clicked on the KMenu icon at the far left of the Desktop Panel (along
the bottom), it didn't fetch up the menu, but caused the whole Panel to flicker
once. The same happened every subsequent time I clicked this icon.

b) I could still use a terminal (LXTerminal) but COULDN'T RUN important commands
like man, kate, or shutdown. I got the following error messages:

$ kate
/usr/bin/kate: /usr/bin/kate: cannot execute binary file
$ shutdown
bash: /sbin/shutdown: cannot execute binary file
$

So the system had been rendered unusable.

Main Question:

Please could you tell me what is going wrong, and how to fix it. As a temporary
get-round, can I perform a re-login or X Window restart or something else that
will put it back to normal?

I'm about to do some repartitioning on my hard drive using gparted on the live
knoppix DVD, and want to be sure that knoppix isn't going to throw a wobbler
while the repartitioning is taking place!

2. I believe the release of the DVD is given by its filename (as shown in
file manager), namely
/media/sr0/KNOPPIX_V7.0.2DVD-2012-05-30-EN.iso .

I have also installed this DVD onto my hard drive, and it shows up as distro
7.0.2, kernel release 3.3.7.

It works fine on the hard drive.


Full Details:

1. The following describes what I had been doing shortly after booting the DVD,
just before it went wrong.

My hard drive is /dev/sda6, and I think I had just mounted it on /media/sda6
so that I could test opening a file on there.

I opened pcmanfm, displayed my home directory on /media/sda6, then
double-clicked on a text file to open it. Nothing happened, so I double-clicked
on it again, and still nothing happened.

Then I noticed that pcmanfm was setup to "Open files with SINGLE click". So
surely the file would have been opened at least once.

I can't remember EXACTLY what I did next in pcmanfm (if anything), but the
result was that pcmanfm exited, I think without me asking it to.

At this point, the system stopped working properly. The problems were as I've
described in the Summary above, ie Desktop Panel flickers when KMenu icon
clicked, and not able to run commands from a terminal.

2. It takes an age to boot the live Knoppix DVD (about 3 minutes) so I don't
want to have to do that every time it goes wrong.

I had the Panel flicker fault (when clicking the KMenu icon) once before, but
on that occasion it was caused by something else. I think I may have been
trying to switch to another Work-space or something, when it happened.

3. In case it's relevant, when I currently boot the DVD, the metacity X window
manager is in place at the end of the boot.

4. While the DVD was booting today, I saw the following on the screen (I don't
know if it's always there). I'm sorry I only caught SOME details of it (the
"..." below are what I can't recall):

"The graphical subsystem could not be started or terminated unexpectedly.
...
Examples:
knoppix ... =radeon ...
..."

Then the boot continued (after a pause?). When the boot finished, THE SYSTEM
BEHAVED THIS TIME. For example, when I double-clicked on a text file in pcmanfm,
two instances of leafpad duly opened the file.

[Harry Kuhman]

I have also installed this DVD onto my hard drive, and it shows up as distro
7.0.2, kernel release 3.3.7.

It works fine on the hard drive.
This leads me to suspect bit rot on the DVD or read problems with the DVD drive. Still, I would boot the DVD with the memtest option and run Memtest86 for a while also. If you have the original ISO file then I would also try burning anther DVD but be very sure to test the DVD after burning it to help confirm that you are not getting reading errors, although that isn't a perfect test against intermittent read errors..

[winger9]

Thanks Harry (#2). How do I boot the DVD with the memtest option, and how do I
run Memtest86, thanks.

I appreciate your comment about bit rot* on the DVD. (*I asume this refers to
deterioration of the physical DVD). I can't discount that possibility (I burned
the DVD about 5 years ago).

But I originally got that Desktop Panel flicker thing (when clicking on the
KMenu icon) within about a year of creating the DVD.

I'm fairly sure I did the md5 checksum on the iso I originally downloaded, and
it was good. I can't remember if I burned the DVD at slow speed, but I don't
think I would have selected a high speed.

I have had the Acer laptop about 5 or 6 years, but my gut feeling is that the
Pioneer DVD drive is reading OK.

[Harry Kuhman]

Read up on Knoppix "cheat codes". memtest (not memtest86)is the parameter to use to run memtest86. Don't use the word knoppix like you do with most other cheat codes (the first parameter is the kernel or program that gets run).

Unfortunately, a high speed burn is usually the default option, so you don't have had to select it. Selecting a low speed burn is even becoming difficult or impossible with some software that wants to look fast. I've lost count of how many times I've seen Knoppix problems that the user swears can't be because of a bad burn but none the less go away when they finally do a low speed burn. There is a lot of redundant error correction information on a CD or DVD. You want that error correction to help fight bit-rot over the years, not to hide marginal results from a high speed burn. I didn't want to believe that it was important to burn at low speed at first either, but years of experience have convinced me it is.

[winger9]

When booting the live DVD, at the boot prompt, I ran

knoppix testcd

The test was taking ages so I went away from the computer. When I came back
(about 25 minutes later), the computer had completely booted, and there was no
message about the testcd results.

Are the results stored somewhere, so that I can look at them, or does the fact
that the computer booted mean that the DVD was found to be fine?

[knp]

Hi all

1- "Burners" and "errors" might be avoided if there was proposed on the
repositaries an adequate "USB_file_installation for direct
installation...Without BURNERS.

2- This idea comes to me because some "dvd-writers fantaisies" and because
of the now widely common "usb-drives".

I hope this kind of file because "knoppix system" is very complete for my needs.

knp

[thriftee]

Flash drives are faster and more reliable. If you have a windoze machine you can download and then burn a USB with RUFUS. Trying to hunt problems on a 5 yr old version isn't worth the effort.