Archive for January, 2010

Quick post: MicroEmacs


2010
01.20

Seems that Linus Torvalds uses this editor to day-to-day work.

I use Emacs too, and my (and not only my) mainly complain is about it’s weight. So let’s try it!

For Debian based (but not only) go to this page and download tha packages you need. It’s very fast!

I’m very happy about this new feature!


2010
01.18

From kernelnewbies.org:

1.8. Easy local kernel configuration

Most people uses the kernel shipped by distros – and that’s good. But some people like to compile their own kernels from kernel.org, or maybe they like following the Linux development and want to try it. Configuring your own kernel, however, has become a very difficult and tedious task – there’re too many options, and some times userspace software will stop working if you don’t enable some key option. You can use a standard distro .config file, but it takes too much time to compile all the options it enables.

To make the process of configuration easier, a new build target has been added: make localmodconfig. It runs “lsmod” to find all the modules loaded on the current running system. It will read all the Makefiles to map which CONFIG enables a module. It will read the Kconfig files to find the dependencies and selects that may be needed to support a CONFIG. Finally, it reads the .config file and removes any module “=m” that is not needed to enable the currently loaded modules. With this tool, you can strip a distro .config of all the unuseful drivers that are not needed in our machine, and it will take much less time to build the kernel. There’s an additional “make localyesconfig” target, in case you don’t want to use modules and/or initrds.


Debian testing as a perfect low-latency audio workstation: software and tweaking


2010
01.14

This post is not completed yet!

I’m very well with Ubuntu Studio 9.10, but I’ve tried last Indamixx Transmission OS. I’m pretty disappointed of the incompleteness of the UI and documentation, but the price was fine so I bought it.

Reading on Creating Digital Music I’ve read some comments about Debian testing as perfect for this, so I’m writing this post keep tracking of the software I install on it and the config tweaking to make it a fully functionable Linux Audio Workstation!

First of all the Debian version.

I choose Debian Testing netinstall. The latest daily build can be found here.

I’ve chosen an alternative desktop (LXDE) under advanced options at the cd-rom boot due to the speed of this light DE. English as language and the most used (default) options for the rest.
The partition (all in /) has been formatted in ext4 to increase speed; Install only the laptop metapackage (obviously the desktop environment) and the SSH server too.

Software installed:

Named as package in Debian; obviously you won’t need all of those (like emacs or gnome-do) but this is my list, not yours…

  • jackd
  • qjackctl
  • ardour
  • mixxx
  • patchage
  • vlc
  • jack-rack
  • sooperlooper
  • wine
  • gnome-do
  • epdfviewer
  • lmms
  • emacs23-nox
  • build-essential
  • libncurses5-dev
  • zlib1g-dev
  • kernel-package
  • network-manager

Kernel compilation:

You need to compile a RT kernel so let’s patch it! In this case I use a 2.6.31 vanilla kernel:

  • wget http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.31.6.tar.bz2
  • wget http://www.kernel.org/pub/linux/kernel/projects/rt/patch-2.6.31.6-rt19.bz2
  • tar xvjf linux-2.6.31.6.tar.bz2
  • cd linux-2.6.31.6/
  • bzcat ../patch-2.6.31.6-rt19.bz2 |patch -p1
  • make clean && make mrproper
  • make menuconfig
    Set the following values:

    • processor type and features -> Preemption mode -> complete preemption
    • processor type and features -> Timer frequency -> 1000Hz
    • Kernel Hacking -> Disable kernel debugging

    And in general disable what you don’t want to use in this kernel (you really need XBOX controller drivers?)

  • make-kpkg clean
  • export CONCURRECY_LEVEL=2
  • time fakeroot make-kpkg –initrd –append-to-version=-rt-20100112 kernel_image kernel_headers (change the date if you want…)
  • Now install all the *.deb packages in the directory

Another (maybe simpler) way to obtain a real time kernel:

  • Add this line to /etc/apt/sources.list:
    deb http://debian.pengutronix.de/debian sid main contrib non-free
  • give a sudo apt-get -q update
  • when error appears give a sudo apt-get -q –allow-unauthenticated install pengutronix-archive-keyring
  • sudo apt-get -q update
  • sudo apt-get install linux-image-2.6-rt-686

That’s it! Now you should have a 2.6.31.2-rt13-1-686 shiny new kernel!

Another (even simpler) way to obtain an updated kernel:

Stole it from the latest Ubuntu Studio!

I did do because I cannot manage my wifi card with the rt kernel included in the fedora repos and seems that the patch give a mess with my Ralink card.

Tweaking:

  • Enabled bash completion (uncomment the entry in /etc/bash.bashrc)
  • Add your local user to the sudo group (Ubuntu like behaviour); as root: adduser youruser sudo
  • Enable real-time support while installing jackd
  • To add a menu entry of an application that does not shows in the menu do that:
    • launch lxshortcuts -o appname.desktop (change appname, obviously)
    • fill all the fields (for example, I use sooperlooper so put “slgui” without quotes in the command field
    • mv appname.desktop /usr/share/applications/
    • Now the applications will show in the “other” menu so you can add it to a panel…
  • This the qjackctl settings to obtain best performances (can be different from yours, feel free to experiment with):
    • Frames/Period: 512
    • Sample Rate: 48000
    • Periods/Buffer: 3

Comparisons:

  • Fully updated Transmission OS (Indamixx): latency 23.2 ms
  • Debian Testing (prepared with this guide): 32 ms
  • For Ubuntu Sudio 9.10 (same jackd settings): 32 ms (as Debian)

Vecchie pubblicita’ sessiste…


2010
01.04

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