[conspire] debugging

[Rick Moen]

Quoting Paul Zander (paulz at ieee.org):

> Looks like we will have an interest CABAL this evening.

Sure.  Also, I'm ahead of the game on food preparation:  Have the pizza
crust ready to roll out, will soon do most of the chopping, etc., and 
have two fresh loaves of garlic bread.

> I am running a desktop with Debian Testing and did an upgrade about 2
> weeks ago.  Recently I have encountered a couple of "glitches" during
> boot up.  I can bring the various log files to cabal to examine, but
> which files?
> 
> Glitch #1.   After grub, there is a message about "No Symbol Table".
> I was going to manually record the exact words, but the warning timed
> out and proceeded.  I have successfully rebooted numerous times.

Web-searching suggests:

Become the root user.  Make sure your backups are current.

grub-install /dev/sdX   #for suitable value of X
update-grub
sync
sync
sync  #Just to make extra-sure the disk caching gets flushed.
reboot


Don't overinterpret the return message 'Successful' when you run those
GRUB utilities.  It means only that the utility completed, not
necessarily that it did anything useful.  E.g., if you specify wrong
target /dev/sdX, grub-install will say 'Successful', but that means 
only 'I successfully completed that futile and wrong-headed action you
told me to do.'

(Default 'grub' in Debian starting with 6.0 'Squeeze' has been GRUB2.
Ugh.)

The diagnostic is unfortunately very non-specific.  It's merely
reflecting the fact that some ELF-format binary object is not able to
find that program's symbol table, a data structure useful for debugging.

  An object file's symbol table holds information needed to locate and
  relocate a program's symbolic definitions and references. 

https://refspecs.linuxbase.org/elf/gabi4+/ch4.symtab.html


_Or_:

You know, you _could_ decide to just ignore the diagnostic.  It's not
exactly the end of the world that some object module somewhere isn't
able to find its symbol table.



> Glitch #2.   After running a week or more, I decided to re-boot.  The PC is dual-boot and there was something I couldn't do with Wine.

See, there's a very frequent theme running through the case history of
people who end up with screwed-up bootloader setups:  A large percentage
of them do dual-booting.

My radical idea:  Use a simple machine configuration, preferably using a
simple bootloader (IMO, no version of GRUB).  Then, leave it alone.


> I made a point of closing all of the applications and windows before
> shutdown.  Later, during the re-boot of Debian, the boot screen froze
> with just three lines of text.  Lots of disk access, but several
> minutes on nothing on the screen.  I turned off power.  This morning
> I booted into Win 7 with no problem and took care of email.  Then I
> opened the laptop and prepared to type transcripts of the error
> messages from the desktop.  As mentioned above, the No symbol table
> warning cleared.  Then I started to copy from the screen:

> /dev/sdc2: clean, 278521/6406144 files, 3916158/25600000 blocks
> >A message about an unreliable temperature sensor.  This message is
> >nothing new.  I have ignored it many many times in past.
> 
> And one more line.
>
> Before I could transcribe the 3rd line, the boot screen started
> scrolling lots of messages.  The boot appeared to finish normally.

OK, so please don't take this the wrong way, but I'm a little confused.
What problem are you seeking to investigate?