Knoppix 7.0.2-EN DVD notes & comments

[ruymbeke]

Hello,
Did someone managed yet to get the 64 bits compile & run time environment working on Knoppix 7.0.2 ?
The steps provided by Klaus for Knoppix 6.7.1 are no longer working (cf link below)
http://knoppix.net/forum/threads/294...l=1#post125222
and my other attempts have failed so far.
Best Regards,
Gilles

[utu]

Greetings, Gilles.
Is your 7.0.2 running a 64-bit kernel?

[ruymbeke]

Hi Utu,
Yes of course.
The following line was working well enough on Knoppix 6.7.1 with the 64 bit Linux kernel:
sudo apt-get -y -t sid --reinstall install libc6 libc6-dev libc6-dev-amd64 gcc-4.6-multilib lib64gcc1
But this does not work any more with Knoppix 7 (7.0.0 nor 7.0.1 nor 7.0.2).
There are conflicting packages that are in use and switching into single user mode (init 1) does not help.
Cheers,
Gilles

[klaus2008]

Hi Gilles,

I have successfully tried the following with Knoppix V7.0.2.

You have to replace the packages libc-bin, libc-dev-bin, libc6, libc6-dev with those of the unstable branch.

Open a terminal an issue

sudo apt-get update
sudo apt-get -d -t unstable install libc-bin libc-dev-bin libc6 libc6-dev
sudo chvt 1
init 2
apt-get -t unstable install libc-bin libc-dev-bin libc6 libc6-dev
chroot /UNIONFS/
apt-get -t unstable -f install
exit
init 5
chvt 5

Now you can install the current packages gcc-4.6-multilib and g++-4.6-multilib from the unstable branch.

 sudo apt-get -y -t unstable install gcc-4.6-multilib g++-4.6-multilib

Download and extract pi_quick_start.tar.gz

Change to your pi_quick_start directory and load start.sh into a text editor. Replace all occurances of "cc" with "gcc -m64". Save the file and exit the text editor.

Set the environment variable CFLAGS:

export CFLAGS=-m64

Run the script:

./start.sh

Best Regards

[ruymbeke]

Hi Klaus,
This works great, thank you very much !
Would you consider adding these 64 bits packages in a future Knoppix DVD
such as this 64bits libraries and compile environment would be ready
to be used by the user when booting with the 64 bit kernel ?
Would you also consider adding the oprofile kernel module ?
Best Regards,
Gilles

PS: I noticed that the "libc" and "ld-linux" 64 bits libraries are now located into "/lib/i386-linux-gnu".
Shouldn't they be located into /lib64 instead (as it is on Knoppix 6.7.1) ?

[otropogo]

I must confess I couldn't quite follow Klaus's explanation on booting 7.0.2 in 64-bit mode, especially since I have no experience in running 64-bit OSs. However, I tried booting with the "knoppix64" argument and when I do, System Monitor shows my PC as having 3.9GB of RAM available, whereas when booting normally, the utility is only showing 2.9GB of RAM. So I assume this means that the 64-bit kernel is working...

[ruymbeke]

Hi otropogo,
Yes you are running a 64 bits kernel since you can see most of your RAM (3.9GB instead of 2.9GB with a 32 bits kernel).
You can also see that you are running a 64bits kernel by running the command "uname -a" from a shell console:
"Linux Microknoppix 3.3.7-64 #40 SMP PREEMPT Tue May 22 08:47:38 CEST 2012 x86_64 GNU/Linux"
As Klaus explained previously, besides the fact that a 64bits kernel allows you to use almost all of your RAM
as most 64 bits applications the 64 bits kernel is also more efficient (runs faster) but at a price of a larger footprint
which is not desirable for a CD/DVD (especially when speed does not really matter for most users and applications),
reason for Klaus to only have the 64 bits Kernel available on his great Knoppix distribution (and have all the libraries
and other applications only as 32 bits code, knowing that 32bits code can be used with a 64bits kernel).
Now if for some reason you really like or need 64 bits native code to run on that platform then you need to have
some extra libraries (as glibc) and other tools to create these 64 bits applications (as gcc) and this is exactly
these installation steps that Klaus explained previously. Hope this helps.
Best Regards,
Gilles

[otropogo]

Hi otropogo,
Yes you are running a 64 bits kernel since you can see most of your RAM (3.9GB instead of 2.9GB with a 32 bits kernel).
You can also see that you are running a 64bits kernel by running the command "uname -a" from a shell console:
"Linux Microknoppix 3.3.7-64 #40 SMP PREEMPT Tue May 22 08:47:38 CEST 2012 x86_64 GNU/Linux"
As Klaus explained previously, besides the fact that a 64bits kernel allows you to use almost all of your RAM
as most 64 bits applications the 64 bits kernel is also more efficient (runs faster) but at a price of a larger footprint
which is not desirable for a CD/DVD (especially when speed does not really matter for most users and applications),
reason for Klaus to only have the 64 bits Kernel available on his great Knoppix distribution (and have all the libraries
and other applications only as 32 bits code, knowing that 32bits code can be used with a 64bits kernel).
Now if for some reason you really like or need 64 bits native code to run on that platform then you need to have
some extra libraries (as glibc) and other tools to create these 64 bits applications (as gcc) and this is exactly
these installation steps that Klaus explained previously. Hope this helps.
Best Regards,
Gilles

Thanks Giles. If I've understood correctly now, the optional kernel allows one to use more than 3.GB of RAM, but not to run 64-bit applications. I gather there may also be some performance loss, when running 32-bit applications on the 64-bit kernel?

[utu]

@ Otropogo

I think part of what Klaus K is saying is that for many/most Linux 'ordinary' Knoppix
users, using 64-bit applications won't show MUCH, if any performance improvement over
using the same 32-bit application. Think spread-sheet, browser, word-processor, etc.

I don't think there should necessarily be ANY performance penalty in using 32-bit
applications with a 64-bit kernel enabled.

[ruymbeke]

Hi Otropogo,
I do not see any reason to not always use a 64bits kernel if your system processor does support it.
Klaus still uses a 32bits kernel as the default because some older machine are not 64bits capable
and it is desirable to have his live CD/DVD to run by default (without tweaks) on most systems.
Best Regards,
Gilles