Posts Tagged ‘Module’

Play Midis on Linux / Make Linux MIDI Ready for the Future – Enable embedded MIDI music to play in a Browser, Play MIDIs with VLC and howto enjoy Midis in Text Console

Wednesday, October 4th, 2017

how-to-play-midi-on-gnu-linux-in-graphic-environment-console-and-browser-midi-synthesizer-and-linux-tux-together

 

Play Midis on Linux or Make Linux MIDI Ready for the Future – Enable embedded MIDI music to play in a Browser, Play MIDIs with VLC and howto enjoy Midis in Text Console HOWTO

 

Playing MIDI has been quite a lot of fun historically,

if you grow up in the days when personal computers were still young and the Sound Blaster was a luxury, before the raise of Mp3 music format, you have certainly enjoyed the beeping of PC Speaker and later on during 386 and 486 / 586 computers the enjoyment of playing tracked music such as S3M and MOD,

in that good days playing MIDI music was the only alternative for PC maniacs who doesn't own a CD Drive (which itself) was another luxury and even thouse who had a CD ROM device, were mainly playing music in CD audio format (.CDA).
Anyhow MIDI was a cheap and a CPU unintensive way to listen to equivalent of favourite popular Audio Songs and for those who still remember many of the songs were recreated in MIDI format, just with a number of synthesized instruments without any voice (as MIDI is usually).

The same was true also for the good old days of raise of Mobile Phones, when polyphonic was a standard as CPU power was low MIDI was a perfect substitute for the CPU heavy Encoded MP3s / OGG and other formats that required a modern for that time Intel CPU running in 50+ Mhz usually 100 / 166Mhz was perfect for the days to play Mp3 but still even on that PCs we listened to Midi songs.

Therefore if you're one of those people like me who still enjoy to play some Midi Music in the year 2017 and feel a bit like Back into the Future movie and a Free Software fan and user, especially if you're a novice GNU  / Linux Free Software user, you will be unpleasently surprised that most today's default Linux distributions doesn't have an easy way to play Midi music format out of the box right after install.

Hence below article aims to give you an understanding on

How you can play Midi Music on GNU / Linux Operating System

First, lets Prepare to load necessery Linux kernel modules to make sure MIDI can be played by soundcard:

In /etc/modules make sure you have the following list of modules loaded:
 

linux-desktop:~# cat /etc/modules
3c59x
snd-emu10k1
snd-pcm-oss
snd-mixer-oss
snd-seq-oss

!Note the modules are working as of time of writting and in time can change to some other modules, depending on how the development of ALSA (Advanced Linux Sound Architecture) goes, and if the developers decide to rename the upmentioned modules

If you just have added the modules to /etc/modules with vim / nano to reload modules into the Linux kernel run:

 

linux-desktop:~# modprobe -a


Secondly, Installing a whole bunch of MIDI music related program tools can be achieved in Debian by installing the multimedia-midi package, e.g.:

 

linux-desktop:~# apt-get install –yes multimedia-midi

 

1. Playing Midi in Graphical environment with a double click using VLC


How to make MIDI easy listanable in Linux graphical environment like GNOME / KDE / XFCE desktop ?

 

If you want to make Midi music execution sa easy as  just clicking on the .MIDI file format on Linux you can do that with a midi extension available for VLC (Video Lan Client) Universal Multi Platform Media Player player

To install it on Debian Ubuntu GNU / Linux
 

# apt-get install –yes vlc-plugin-fluidsynth

 

Необходимо е да се изтеглят 6754 B архиви.
След тази операция ще бъде използвано 35,8 kB допълнително дисково пространство.
Изт:1 http://deb.debian.org/debian stretch/main amd64 vlc-plugin-fluidsynth amd64 2.2.6-1~deb9u1 [6754 B]
Изтеглени 6754 B за 0с (33,6 kB/сек)           
Selecting previously unselected package vlc-plugin-fluidsynth:amd64.
(Reading database … 382976 files and directories currently installed.)
Preparing to unpack …/vlc-plugin-fluidsynth_2.2.6-1~deb9u1_amd64.deb …
Unpacking vlc-plugin-fluidsynth:amd64 (2.2.6-1~deb9u1) …
Setting up vlc-plugin-fluidsynth:amd64 (2.2.6-1~deb9u1) …
Processing triggers for libvlc-bin:amd64 (2.2.6-1~deb9u1) …


Besides making your MIDI play on the GUI environment easy as a a point and click VLC will also be able to play MIDIs on GNU / Linux from your favourite browser (nomatter Firefox / Chrome or Opera), even though the player would play in a new PopUP Window it is easy to select once MIDI file from a random website for example – here is a directory listing of Webserver with Doom II Soundtrack in MIDI format , click over any file from list and Choose option for VLC to always remember that MIDI files has to be opened with VLC player.
 


2. Enable Firefox / IceWeasel browser to Support Website embedded MIDI files

 

 

So VLC could make you listen the downloadable MIDIs from Web pages but,
 

What if you have stumbled on an old website which was configured with very OLD HTML Code to play some nice music (or even different MIDI songs) for each part of the website (for each webpage) and you want to have the Websites created with embedded MIDIs to automatically play on Linux oncce you visit the site?


Sadly default support in Browser for MIDI across all GNU / Linux, I've used so far never worked out of the box, not that still anyone is developing modern websites with MIDIs, but still for the sake of backward compitability and for sake of interactivity it is worthy to enable embedded MIDI support in Linux

But with a couple of tunings as usual GNU / Linux can do almost everything, so here is how to enable embedded browser support for Midi on Linux (That should work with minor modifications not only on Debian / Ubuntu / ArchLinux but also on Fedoras, CentOS etc.
If you try it on any of this distributions, please drop a short comment and tell me in few lines how you made embedded midi worked on that distros.

 

apt-get install –yes timidity mozplugger

Next do restart firefox

Sometimes in order to work you might need to delete /home/[YOUR_USERNAME]/.mozilla/pluginreg.dat and restart firefox again, e.g. make a backup and give it a try:

 

cp -rpf /home/hipo/.mozilla/pluginreg.dat /home/hipo/.mozilla/pluginreg.dat.bak
rm -f /home/hipo/.mozilla/pluginreg.dat

 

Another good tip as talking for embedding MIDI support is to embed XPDF to render PDF pages inside the Browser, by default this is done by GNOME's Evince PDF reader but as it is sometimes buggy and might crash it is generally a good idea to switch to xpdf instead, if for some reason PDF is not directly displaying in browser or suddenly stopped working after some distro uipgrade, you might want to do below as well:
 

apt-get install xpdf

vim /etc/mozpluggerrc

Fin d and Comment out the line starting with:

It should look like this afterwards:

 Repeat Swallow ….
 

text/x-pdf: pdf: PDF file
#      repeat swallow(documentShell) fill: acroread -geometry +9000+9000 +useFrontEndProgram "$file"
        repeat noisy swallow(Xpdf) fill: xpdf -g +9000+9000 "$file"
        repeat noisy swallow(gv) fill: gv –safer –quiet –antialias -geometry +9000+9000 "$file"


 

3. Play Midi music in Linux text console / terminal


There is a console tool that historically has been like the Linux standard for playing midis over the years as I remember, its called timidity

 


To install timidity on .Deb based Linux:
 

linux-desktop:~$ su root
Password:
linux-desktop:~# apt-get install –yes timidity

Необходимо е да се изтеглят 0 B/580 kB архиви.
След тази операция ще бъде използвано 0 B допълнително дисково пространство.
(Reading database … 382981 files and directories currently installed.)
Preparing to unpack …/timidity_2.13.2-40.5_amd64.deb …
Unpacking timidity (2.13.2-40.5) over (2.13.2-40.5) …
Processing triggers for menu (2.1.47+b1) …
Processing triggers for man-db (2.7.6.1-2) …
Setting up timidity (2.13.2-40.5) …
Processing triggers for menu (2.1.47+b1) …

 

To test your new MIDI Synthesizer tool and make the enjoyment full you can download Doom 2 extracted MIDI Soundtrack from here
 

Once you have downloaded above Metal MIDI DOOM old school arcade soundtrack and untarred it into your home directory be it ~/doom-midis

A remark to make here is timidity is quite CPU intensive, but on modern Dual and Quad-Core PC Notebooks, the CPU load is not of a big concern.

To test and play with timidity:
 

linux-desktop~$ timidity ~/mp3/midis/*


timidity-playing-doom-midi-bunny-song-on-debian-stretch-gnome-terminal-screenshot
 

hipo@jericho:~/mp3/midis$ aplaymidi -l
 Port    Client name                      Port name
 14:0    Midi Through                     Midi Through Port-0
128:0    TiMidity                         TiMidity port 0
128:1    TiMidity                         TiMidity port 1
128:2    TiMidity                         TiMidity port 2
128:3    TiMidity                         TiMidity port 3

 


We have also the playmidi  (simple midi text console terminal player), which historically was working quite decent and I use it to in the past on my RedHat 6.0 and RedHat 7.0 to listen to my .MID format files but unfortunately as of time of writting something is wrong with it, so when I try to play MIDIs with it instead of timidity I get this erro:

 

$ playmidi *.mid
Playmidi 2.4 Copyright (C) 1994-1997 Nathan I. Laredo, AWE32 by Takashi Iwai
This is free software with ABSOLUTELY NO WARRANTY.
For details please see the file COPYING.
open /dev/sequencer: No such file or directory

Even though I tried hard to resolve that error by loading various midi related MIDI modules and following a lot of the suggestions online on how to  make /dev/sequencer work again it was all no luck.
 

Some people back in the distant year 2005, reported the problem was solved by simply loading snd-seq

But as of time of writting:

 

# modprobe snd-seq

 

Some people said in archlinux's Forum

/dev/sequencer sequencer: No such file or directory

 

is solved by loading snd-seq-oss kernel module, but on my Debian Linux 9.1 Stretch, this ain't work as well :

 

root@jericho:/home/hipo/mp3/midis# modprobe snd-seq-oss
modprobe: FATAL: Module snd-seq-oss not found in directory /lib/modules/4.9.0-3-amd64
root@jericho:/home/hipo/mp3/midis# uname -a;
Linux jericho 4.9.0-3-amd64 #1 SMP Debian 4.9.30-2+deb9u5 (2017-09-19) x86_64 GNU/Linux


Another invention of mine was to try to also link /dev/snd/seq to /dev/sequencer but this produced no positive result either:

 

# ln -sf /dev/snd/seq /dev/sequencer
# ls -al /dev/sequencer
lrwxrwxrwx 1 root root 12 окт  4 16:48 /dev/sequencer -> /dev/snd/seq


Note that after lining in that way I got following error with my attempt to play MIDIs with playmidi

# playmidi *.mid
Playmidi 2.4 Copyright (C) 1994-1997 Nathan I. Laredo, AWE32 by Takashi Iwai
This is free software with ABSOLUTELY NO WARRANTY.
For details please see the file COPYING.
there is no soundcard


Anyhow on some other Linux distributions (especially with Older Kernel versions), some of the above 3 suggested Fix might work perfectly fine so if you have some time give it a try please and drop me  a comment on how it went, you will help the GNU / Linux community out there that way.

Well never mind the bollocks, so

Now back to where I started timidity even though it will play fine it will not give any indication on the lenght of the midi song (precious information such as how much time is left until the end is over).

Hence if you prefer a player that gives you an indicator on how much is left towards the end length of each of the played MIDI file you can give a try to wildmidi:

 

linux-desktop:~$ apt-cache show wildmidi|grep -i description -A 2

Description-en: software MIDI player
 Minimal MIDI player implementation based on the wildmidi library that
 can either dump to WAV or playback over ALSA. It is intended to

Description-md5: b4b34070ae88e73e3289b751230cfc89
Homepage: http://www.mindwerks.net/projects/wildmidi/
Tag: implemented-in::c, role::program, sound::midi, sound::player,

Description: software MIDI player
Description-md5: 4673a7051f104675c73eb344bb045607
Homepage: http://wildmidi.sourceforge.net/
Bugs: https://bugs.launchpad.net/ubuntu/+filebug


If yet not installed install it after becoming admin user:

 

linux-desktop:~$ su root
Password:

linux-desktop:~# apt-get install –yes wildmidi


wildmidi is much less CPU intensive (it uses gstreamer to play (Gstreamer – open source multimedia framework)

And next give it a try by running:

 

linux-desktop:~$ wildmidi ~/mp3/midis/*

 

wildmidi-midi-lenght-status-text-console-player-for-linux-ubuntu-debian-fedora-suse

 

 

4. Editting MIDI files with Free Software and Proprietary MIDI Editor Programs

 


If you want a professional software that can play Midi in a fuzzy interactive GUI way and have some extra possibilities to edit MIDIs and other format give a try to Muse Sequencer:
 

 

linux-desktop:~$ sudo apt-get install –yes muse

The following NEW packages will be installed:
  muse
0 upgraded, 1 newly installed, 0 to remove and 38 not upgraded.
Need to get 5814 kB of archives.
After this operation, 21.0 MB of additional disk space will be used.
Get:1 http://deb.debian.org/debian stretch/main amd64 muse amd64 2.1.2-3+b1 [5814 kB]
Fetched 5814 kB in 2s (2205 kB/s)                             
    are supported and installed on your system.
Preconfiguring packages …
Selecting previously unselected package muse.
(Reading database … 382981 files and directories currently installed.)
Preparing to unpack …/muse_2.1.2-3+b1_amd64.deb …
Unpacking muse (2.1.2-3+b1) …
Processing triggers for mime-support (3.60) …
Processing triggers for desktop-file-utils (0.23-1) …
Processing triggers for doc-base (0.10.7) …
Processing 1 added doc-base file…
Registering documents with scrollkeeper…
Processing triggers for man-db (2.7.6.1-2) …
Processing triggers for shared-mime-info (1.8-1) …
Unknown media type in type 'all/all'
Unknown media type in type 'all/allfiles'
Processing triggers for gnome-menus (3.13.3-9) …
Setting up muse (2.1.2-3+b1) …
Processing triggers for hicolor-icon-theme (0.15-1) …


 

Below is short description what Muse can do for you:

 

MusE is a MIDI/audio sequencer with recording and editing capabilities.
 Some Highlights:
 

  * Standard midifile (smf) import-/export.
  * Organizes songs in tracks and parts which you can arrange with
    the part editor.
  * MIDI editors: pianoroll, drum, list, controller.
  * Score editor with high quality postscript printer output.
  * Realtime: editing while playing.
  * Unlimited number of open editors.
  * Unlimited undo/redo.
  * Realtime and step-recording.
  * Multiple MIDI devices.
  * Unlimited number of tracks.
  * Sync to external devices: MTC/MMC, Midi Clock, Master/Slave.
  * Audio tracks, LADSPA host for master effects.
  * Multithreaded.
  * Uses raw MIDI devices.
  * XML project file.
  * Project file contains complete app state (session data).
  * Application spanning Cut/Paste Drag/Drop.

 

linux-desktop~:$ muse

muse-advanced-midi-editor-free-software-for-linux

 

Below is another non-free program that you might, try if MusE doesn't fit your needs (is not rich enough for editting capabilities is bitwig (though I don't recommend since it is not free software)

bitwig – Bitwig Studio is a multi-platform music-creation system for production, performance and DJing, with a focus on flexible editing tools and a super-fast workflow.
 


bitwig-midi-and-audio-non-free-software-advanced-useful-sound-editor-for-linx


 

5. Some examples for Text editing and MIDI Conversion to CSV and ABC file formats There is pretty much more

For the MIDI Extremists who or people that create MIDIs and want to learn how a MIDI is made (the content of it etc.), I suggest you take a look at these 3 command line MIDI editing / conversion tools
 

  • midi2abc – A little tool to create MIDI formats to ABC format
  • midi2csv – Conver tour Favourite MIDI files to CSV for educational purposes so see what Channels, Tracks and Time Intervals is a MIDI song mad
  • midicopy – Copy selected, track, channel, time interval of MIDI file to another MIDI file3

 

Well, that's all folks now enjoy your MIDIs and don't forget to donate, as I'm jobless at the moment and the only profit I make is just a few bucks out of advertisement on this blog.
 

Fix “Approaching the limit on PV entries, consider increasing either the vm.pmap.shpgperproc or the vm.pmap.pv_entry_max tunable.” in FreeBSD

Monday, May 21st, 2012

bsdinstall-newboot-loader-menu-pv_entries_consider_increasing_vm_pmap_shpgrepproc

I'm running FreeBSD with Apache and PHP on it and I got in dmesg (kernel log), following error:

freebsd# dmesg|grep -i vm.pmap.shpgperproc
Approaching the limit on PV entries, consider increasing either the vm.pmap.shpgperproc or the vm.pmap.pv_entry_max tunable.
Approaching the limit on PV entries, consider increasing either the vm.pmap.shpgperproc or the vm.pmap.pv_entry_max tunable.
Approaching the limit on PV entries, consider increasing either the vm.pmap.shpgperproc or the vm.pmap.pv_entry_max tunable.
Approaching the limit on PV entries, consider increasing either the vm.pmap.shpgperproc or the vm.pmap.pv_entry_max tunable.
Approaching the limit on PV entries, consider increasing either the vm.pmap.shpgperproc or the vm.pmap.pv_entry_max tunable.

The exact FreeBSD, Apache and php versions I have installed are:
 

freebsd# uname -a ; httpd -V ; php –version
FreeBSD pcfreak 7.2-RELEASE-p4 FreeBSD 7.2-RELEASE-p4 #0: Fri Oct 2 12:21:39 UTC 2009 root@i386-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC i386
Server version: Apache/2.0.64
Server built: Mar 13 2011 23:36:25Server's Module Magic Number: 20050127:14
Server loaded: APR 0.9.19, APR-UTIL 0.9.19
Compiled using: APR 0.9.19, APR-UTIL 0.9.19
Architecture: 32-bit
Server compiled with….
-D APACHE_MPM_DIR="server/mpm/prefork"
-D APR_HAS_SENDFILE
-D APR_HAS_MMAP
-D APR_HAVE_IPV6 (IPv4-mapped addresses enabled)
-D APR_USE_FLOCK_SERIALIZE
-D APR_USE_PTHREAD_SERIALIZE
-D SINGLE_LISTEN_UNSERIALIZED_ACCEPT
-D APR_HAS_OTHER_CHILD
-D AP_HAVE_RELIABLE_PIPED_LOGS
-D HTTPD_ROOT="/usr/local"
-D SUEXEC_BIN="/usr/local/bin/suexec"
-D DEFAULT_PIDLOG="/var/run/httpd.pid"
-D DEFAULT_SCOREBOARD="logs/apache_runtime_status"
-D DEFAULT_LOCKFILE="/var/run/accept.lock"
-D DEFAULT_ERRORLOG="logs/error_log"
-D AP_TYPES_CONFIG_FILE="etc/apache2/mime.types"
-D SERVER_CONFIG_FILE="etc/apache2/httpd.conf"
PHP 5.3.5 with Suhosin-Patch (cli) (built: Mar 14 2011 00:29:17)
Copyright (c) 1997-2009 The PHP Group
Zend Engine v2.3.0, Copyright (c) 1998-2010 Zend Technologies
with eAccelerator v0.9.6.1, Copyright (c) 2004-2010 eAccelerator, by eAccelerator

After a bunch of research a FreeBSD forums thread , I've found the fix suggested by a guy.

The solution suggested in the forum is to raise up vm.pmap.pv_entry_ma to vm.pmap.pv_entry_max=1743504, however I've noticed this value is read only and cannot be changed on the BSD running kernel;

freebsd# sysctl vm.pmap.pv_entry_max=1743504
sysctl: oid 'vm.pmap.pv_entry_max' is read only

Instead to solve the;

Approaching the limit on PV entries, consider increasing either the vm.pmap.shpgperproc or the vm.pmap.pv_entry_max tunable.
, I had to add in /boot/loader.conf

vm.pmap.pde.mappings=68
vm.pmap.shpgperproc=500
vm.pmap.pv_entry_max=1743504

Adding this values through /boot/loader.conf set them on kernel boot time. I've seen also in the threads the consider increasing either the vm.pmap.shpgperproc is also encountered on FreeBSD hosts running Squid, Dansguardion and other web proxy softwares on busy hosts.

This problems are not likely to happen for people who are running latest FreeBSD releases (>8.3, 9.x), I've read in same above post in newer BSD kernels the vm.pmap is no longer existing in newer kernels.

How to fix Thinkpad R61i trackpoint (mouse pointer) hang ups in GNU / Linux

Wednesday, February 1st, 2012

Earlier I've blogged on How to Work Around periodically occuring TrackPoint Thinkpad R61 issues on GNU / Linux . Actually I thought the fix I suggested there is working but I was wrong as the problems with the trackpoint reappeared at twice or thrice a day.

My suggested fix was the use of one script that does periodically change the trackpoint speed and sensitivity to certain numbers.

The fix script to the trackpoint hanging issue is here

Originally I wrote the script has to be set to execute through crontab on a periods like:

0,30 * * * * /usr/sbin/restart_trackpoint.sh >/dev/null 2>&1

Actually the correct values for the crontab if you use my restart_trackpoint.sh script are:

0,5,10,15,20,25,30,35,40,45,50,55,58 * * * * /usr/sbin/restart_trackpoint.sh >/dev/null 2>&3

ig it has to be set the script is issued every 5 minutes to minimize the possibility for the Thinkpad trackpoint hang up issue.

One other thing that helps if trackpoint stucks is setting in /etc/rc.local is psmouse module to load with resetafter= parameter:

echo '/sbin/rmmod psmouse; /sbin/modprobe psmouse resetafter=30' >> /etc/rc.local

 

How to fix Pulseaudio and Skype crappy sound glitches, choppy sound and crackling on Debian GNU / Linux

Tuesday, January 10th, 2012

I've experienced plenty of problems with Pulseaudio and Skype output sound hell crappy. This stupid proprietary program Skype is a total crap … Anyways again thanks to ArchLinux's wiki, I've used the two mentioned steps to fix all this Skype in / out problems …

1. Fix problems with Glitches, voice skips and crackling In file /etc/pulse/default.pa its necessery to substitute the line;

load-module module-udev-detect

with

load-module module-udev-detect tsched=0

2. Resolve Choppy sound in (Pulseaudio) -> Skype

In /etc/pulse/daemon.conf two lines has to be also substituted:

; default-sample-rate = 44100

Should become;

default-sample-rate = 48000

3. Change /etc/default/pulseaudio to allow dynamic module loading

It is a good idea to the default settings from DISALLOW_MODULE_LOADING=1 to DISALLOW_MODULE_LOADING=0 .This step is not required and I'm not sure if it has some influence on solving sound in / out problems with Skype but I believe it can be helpful in some cases..

So in /etc/default/pulseaudio Substitute:

DISALLOW_MODULE_LOADING=1

to;

DISALLOW_MODULE_LOADING=0

4. Restart PulseAudio server

After the line is changed and substituted a restart of PulseAudio is required. For PulseAudio server restart a gnome session logout is necessery. Just LogOff logged Gnome user and issue cmd:

debian:~# pkill pulseaudio

This will kill any left pulseaudio server previous instances.
 

How to disable IPv6 on Debian / Ubuntu / CentOS and RHEL Linux

Friday, December 9th, 2011

I have few servers, which have automatically enabled IPv6 protocols (IPv6 gets automatically enabled on Debian), as well as on most latest Linux distribituions nowdays.

Disabling IPv6 network protocol on Linux if not used has 2 reasons:

1. Security (It’s well known security practice to disable anything not used on a server)
Besides that IPv6 has been known for few criticil security vulnerabilities, which has historically affected the Linux kernel.
2. Performance (Sometimes disabling IPv6 could have positive impact on IPv4 especially on heavy traffic network servers).
I’ve red people claiming disabling IPv6 improves the DNS performance, however since this is not rumors and did not check it personally I cannot positively confirm this.

Disabling IPv6 on all GNU / Linuces can be achieved by changing the kernel sysctl settings net.ipv6.conf.all.disable_ipv6 by default net.ipv6.conf.all.disable_ipv6 equals 1 which means IPv6 is enabled, hence to disable IPv6 I issued:

server:~# sysctl net.ipv6.conf.all.disable_ipv6=0

To set it permanently on system boot I put the setting also in /etc/sysctl.conf :

server:~# echo 'net.ipv6.conf.all.disable = 1 >> /etc/sysctl.conf

The aforedescribed methods should be working on most Linux kernels version > 2.6.27 in that number it should work 100% on recent versions of Fedora, CentOS, Debian and Ubuntu.

To disable IPv6 protocol on Debian Lenny its necessery to blackist the ipv6 module in /etc/modprobe.d/blacklist by issuing:

echo 'blacklist ipv6' >> /etc/modprobe.d/blacklist

On Fedora / CentOS there is a another universal “Redhat” way disable IPv6.

On them disabling IPv6 is done by editting /etc/sysconfig/network and adding:

NETWORKING_IPV6=no
IPV6INIT=no

I would be happy to hear how people achieved disabling the IPv6, since on earlier and (various by distro) Linuxes the way to disable the IPv6 is probably different.
 

Alto to stop Iptables IPV6 on CentOS / Fedora and RHEL issue:

# service ip6tables stop

# service ip6tables off

How to fix multiple instance music streams with sound card (Intel 82801I ICH9 Family) alsa sound problems on Ubuntu 11.04 GNU / Linux

Thursday, October 27th, 2011

Ubuntu Logo Sound / Pulseaudio multiple sound channel issues

The Ubuntu Linux installed previously on Acer ASPIRE 5736Z on my sisters notebook works quite fine. However today she complained about an issue with her sound. The explanation of the problem she faced is:

When she plays a movie file and pauses it and then switches to a music player, suddenly the notebook sound disappears completely until she restarts all the running programs using the sound server. The Acer Aspire is used with a GNOME Desktop, hence my bet was the issues are most probably caused by some kind of mess happening inside Pulseaudio or the way Alsa loaded kernel drivers handles the multiple sound channel streams.

I’m using GNU / Linux for more than 11 years now and I have faced the same sound issues so many times, so when I heard about the problem I thought its pretty normal.
Anyways, what was really irritating in these situation is that when her laptop sound disappears a video or sound files which are to be played by Mozilla Firefox Browser or Chrome are also loosing the sound.
This causes big issues, especially taking in consideration the fact that she had no idea about computers and is a GUI Desktop user, who have no idea how to restart the pulseaudio server to fix the problem etc.

As a good brother, I took the time to check about the issues related to the specific model of Audio Module Hardware / Sound Card, first I checked the exact model of audio the Acer Aspire 5736Z is equipped with:

stanimiraaaa@Ubuntu-Aspire-5736Z:~$ lspci |grep -i audio
00:1b.0 Audio device: Intel Corporation 82801I (ICH9 Family) HD Audio Controller (rev 03)

I checked about any reported other users issues on the net and I found a user somewhere (lost the link), complaining he is experiencing the same sound oddities on his Acer ASPIRE

The fix he suggested is actually quite simple and comes to adding a simple line to /etc/modprobe.d/alsa-base.conf :

stanimiraaaa@Ubuntu-Aspire-5736Z:~$ sudo su -
[sudo] password for stanimiraaaa:
root@Ubuntu-Aspire-5736Z:~# echo 'options snd_hda_intel model=auto' >> /etc/modprobe.d/alsa-base.conf

Next I restartarted to make the new settings take effect. Its also possible to do it without restart, by unloading and loading the alsa module but I’m a lazy kind of person and the machine is notablyunimportant so why should I bother 😉

One important note here is that I removed also an .asoundrc file, that I created some long time ago and this file might have been creating also some sound issues, the content of ~/.asoundrc, before I delete it in her home user, was like so:

stanimiraaaa@Ubuntu-Aspire-5736Z:~$ cat ~/.asoundrc
pcm.!default {
type hw
card 1
device 0
}
ctl.!default {type hw
card 1
device 0
}
stanimiraaaa@Ubuntu-Aspire-5736Z:~$ rm -f .asoundrc

Doing this minor changes to the Ubuntu system erradicated the sound problems and now the sound with simultaneous sound channel streams works just perfect! Thx God 😉

How to install php mbstring support (add php mbstring module) on CentOS 5.5

Tuesday, August 2nd, 2011

I needed to install support for mbstring, as it was required by a client hosted on one of the servers running on CentOS 5.5.

Installation is quite straight forward as php-mbstring rpm package is available, here is how to install mbstring:

[root@centos [~]#yum install php-mbstring
...

Further on a restart of Apache or Litespeed and the mbstring support is loaded in php.
On some OpenVZ CentOS virtual servers enabling the php-mbstring might require also a complete php recompile if php is not build with the –enable-mbstring

If thus the mbstring has to be enabled on an OpenVZ server with php precompile, this can be easily done with cpeeasyapache , like so

server: ~# cd /home/cpeasyapache/src/php-5.2.9
server: php-5.2.9# cat config.nice |head -n $(($(cat config.nice |wc -l) - 1)) >> config.nice.new;
server: php-5.2.9# echo "'--enable-mbstring' \" >> config.nice.new; echo '"$@"' >> config.nice.new
server: php-5.2.9# mv config.nice config.nice.orig; mv config.nice.new config.nice

After that follow the normal way with make, make install and make install modules , e.g.:

server: php-5.2.9# make && make install && make install modules

Next the php-mbstring is enabled enjoy 😉

How to install Skype on 64 bit Ubuntu (amd64) architecture

Sunday, July 17th, 2011

It seems Skype has troubles installing on 64 bit Ubuntu via Ubuntu’s Graphical Package Install manager which in Ubuntu 11.04 is called (Ubuntu Software Center)

During my attempt to take advantage of the nice GUI apt frontend, I encontered the error:
Wrong Architecture amd64

And Skype install failed, as you see in below’s picture (which you might be unable to read since it’s stating the error in Bulgarian 😉

error Ubuntu 11.04 Skype Install error in architecture amd64

The error is quite understandable, since the Skype deb package which tried to install was built for the i386 architecture.
Since the Software Center was not intelligent enough to work around the issue, I finally fixed it myself using the good old apt-get in terminal, like so:

root@ubuntu:~# apt-get install skype
...

apt did not even complain that the package had a different architecture for i386 and installed skype without any errors as well Skype worked immediately even though the arthictural difference.
This is probably because even though it’s a amd64 Ubuntu it has a kernel module loaded to support i386 binaries 😉
Now my sister can enjoy her skype on the shiny Ubuntu 😉

How to load custom Kernel (tun) module in CentOS and RHEL Linux

Thursday, July 14th, 2011

kernel module load on boot in CentOS and Fedora

Just recently it was necessery to load up a tun kernel module on few CentOS Linux servers.

I’m using Debian on daily basis, and everybody that had even little of experience with Debian should already be aware about the existence of the handy:
/etc/modules file.
On Debian to enable a certain kernel module to load up on Linux boot, all necessery is to just place the kernel module name in /etc/modules.
For example loading the tun tunneling kernel module I issue the command:

debian:~# echo tun >> /etc/modules

I wondered if CentOS, also supports /etc/modules as it was necessery now to add this tun module to load up on CentOS’s boot.
After a bit of research I’ve figured out CentOS does not have support for adding modules names in /etc/modules , anyhow after consulting CentOS documentation on http://www.centos.org/docs/5/html/Deployment_Guide-en-US/s1-kernel-modules-persistant.html , I found CentOS and RHEL use /etc/rc.modules instead of Debian’s /etc/modules to load up any custom kernel modules not loaded by default during system boot.

Therefore instructing the RHEL Linux to load up my desired tun module in kernel on next boot was as easy as executing:

[root@centos ~]# echo 'modprobe tun' >> /etc/rc.modules
[root@centos ~]# chmod +x /etc/rc.modules

Now on next boot CentOS will load up the tun module in kernel. Achiving the same module load up is also possible through /etc/rc.local , but it’s not recommended way as /etc/rc.local would load up the kernel module after all of the rest init boot scripts complete and therefore will load up the module slightly later, at the final boot stage.

How to fix “Fatal error: Call to undefined function: curl_init()” on FreeBSD and Debian

Saturday, June 18th, 2011

After installing the Tweet Old Post wordpress plugin and giving it, I’ve been returned an error of my PHP code interpreter:

Call to undefined function: curl_init()

As I’ve consulted with uncle Google’s indexed forums 😉 discussing the issues, I’ve found out the whole issues are caused by a missing php curl module

My current PHP installation is installed from the port tree on FreeBSD 7.2. Thus in order to include support for php curl it was necessery to install the port /usr/ports/ftp/php5-curl :

freebsd# cd /usr/ports/ftp/php5-curl
freebsd# make install clean

(note that I’m using the php5 port and it’s surrounding modules).

Fixing the Call to undefined function: curl_init() on Linux hosts I suppose should follow the same logic, e.g. one will have to install php5-curl to resolve the issue.
Fixing the missing curl_init() function support on Debian for example will be as easy as using apt to install the php5-curl package, like so:

debian:~# apt-get install php5-curl
...

Now my tweet-old-post curl requirement is matched and the error is gone, hooray 😉