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-   -   Check boot process line by line (http://www.linuxquestions.org/questions/slackware-14/check-boot-process-line-by-line-4175471134/)

textillis 07-27-2013 12:38 PM

Check boot process line by line
 
Is there a command I can put in /etc/lilo.conf or /boot/ somewhere so that I can check the boot sequence line by line?

thanks

theNbomr 07-27-2013 01:08 PM

None that I know of. When I need to do something like that, I set the host up to use a serial console, then attach another computer running some serial terminal software such as C-Kermit or minicom (or on a Windows host, hyperterm). Then you can see all of the console output, scrolling back as necessary to see the earliest messages. Requires having a bootloader that can use a serial console for the most complete results.

--- rod.

textillis 07-27-2013 01:24 PM

>Nbomr;
thanks for your response; though that really surprises me: i'd have thought this was something that
would almost be de rigour for debugging purposes ...

but what do i know?

only been here 5 mins :)

thanks again

willysr 07-27-2013 01:38 PM

some of them can be observed in /var/log/dmesg and /var/log/messages

Didier Spaier 07-27-2013 04:06 PM

You can see very early messages if you append kernel parameter "earlyprintk=vga" or "earlyprintk=serial[,ttySn[,baudrate]]", for instance, to the command line at boot time.

kernel and driver developpers can also use "ddebug_query= [KNL,DYNAMIC_DEBUG]"

See /usr/src/linux/Documentation/kernel-pameters.txt and /usr/src/linux/Documentation/dynamic-debug-howto.txt to know more.

Small tip: when a program displays data on the screen faster than you can read it, you can stop its execution with Ctrl+s and resume it with Ctrl+q

This is a reminiscence of controlling the flow of data on a communication line (e.g. RS232 serial) sending the "XOFF" (or "Transmit off) and XON (or Transmit on) signals, which was useful when the receiver couldn't process the data as fast as they were sent, see this page.

For the records this reminds me that this kind of software flow control have been used for connections between industrial terminals and a mini computer at the super high speed of 1200 bits per second in a project of which I was in charge 33 years ago...

H_TeXMeX_H 07-28-2013 03:12 AM

One thing you can do is increase the output buffer size for the console, and then scroll all the way up and go line by line.

solarfields 07-28-2013 03:45 AM

textillis,

is there something specific you are looking for? may be you can extract it from dmesg?

textillis 07-28-2013 08:34 AM

>Solarfields
 
Quote:

Originally Posted by solarfields (Post 4998234)
textillis,

is there something specific you are looking for? may be you can extract it from dmesg?

I've not used dmesg yet, so I'll <man dmesg> ... cool, thanks.

In the meantime, I did manage to find what I was looking for by applying ctrl+s/ctrl+q, as per Didier's tip.

Edit: mention of LifeCam removed so as to disambiguate thread.
thanks for response!

solarfields 07-28-2013 05:35 PM

What is DeadCam 3000? A camera? Do you know if somebody has managed to get it working on another distro?

octoberblu3 07-28-2013 06:05 PM

I'm guessing you mean a MS Lifecam 3000.

If you are trying to use it with something like skype and just getting a green screen, then you may need to make a small shell script to load a compatibility library to make it work right.

Try running:

LD_PRELOAD=/usr/lib/libv4l/v4l1compat.so /usr/bin/skype


Also, in the future, you might want to mention your root problem in the original post so we can help you get down the right path sooner.

textillis 07-29-2013 03:31 AM

>Solarfields

That was me being flippant, sorry.
I thought the brand was known well enough for me to distort its name and still have people recognize it:

it is a LifeCam from microsoft and I can't get it working on slackware, and no-one else I've read here at LQ has either.
Yet it works fine on my Mint Linux system (?)

textillis 07-29-2013 03:34 AM

Quote:

Also, in the future, you might want to mention your root problem in the original post so we can help you get down the right path sooner.
By "root problem" i take it you meant "boot problem", which is clearly outlined in OP.
cheers :)

solarfields 07-29-2013 05:24 AM

Quote:

it is a LifeCam from microsoft and I can't get it working on slackware, and no-one else I've read here at LQ has either
ye i finally got the pun :)

octoberblu3 07-29-2013 02:37 PM

Quote:

Originally Posted by textillis (Post 4998719)
By "root problem" i take it you meant "boot problem", which is clearly outlined in OP.
cheers :)

Ok, no problem. I was taking all of this as a means to diagnose the webcam not working. But of course, it never hurts to learn how to find things yourself.

textillis 07-29-2013 04:53 PM

>october
>solar

I've started a new thread on lifecam.
thanks to both for time taken :)


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