waelchatila.com - Unix/Linux category

RXTX on Gumstix

Fri, 24 Aug 2007 17:10:00 GMT

Since it could be tricky to get the RXTX sources compiling properly for the gumstix platforms I thought I'd spare anyone the pain by providing my binaries.

librxtxSerial_PXA255.so (Connex / Basix)
librxtxSerial_PXA270.so (Verdex)

However, since you're here, I would advise against using java on the gum. Sure, the programs themselves are a breeze to develop, but getting jam and classpath to compile and run properly can very well take a considerable amount of time. Just think of the reason why you are reading this. Chances are you probably have troubles getting the RXTX sources to compile or run smoothly. Just do yourself a favor, write it in small fast c/c++ or something.

How to move a subversion repository to another server

Tue, 06 Mar 2007 23:33:00 GMT

My closet server died last night. No big deal it was over ten years old and was running at 233MHz...besides it was my wife's old computer hehe. My friend Imran gave me one of his old work machines and I've been moving stuff over. Since I had a svn repository on the old machine the situation presented itself with a problem to move the whole repository. Luckily the good people behind svn have thought about this and provide out-of-the box commands to do this.

On the old server machine do.

svnadmin dump repositoryPath > repository.dumpfile

File transfer the repository.dumpfile file to the new server machine and over there do

cd /path/to/new-repository-parent-directory
svnadmin create repository-name
svnadmin load repository-name < repository.dumpfile

Then on your client type

svn switch --relocate oldurl newurl

AJAX Remote Controlled Lego Robot

Thu, 13 Jul 2006 11:00:33 GMT

This article shows how to remote control a real world lego robot using AJAX technology.

Installing ZyXEL G-360 Wireless 802.11g+ on Fedora Core 4

Mon, 16 Jan 2006 09:33:21 GMT

Instructions are based and extended on the instruction found on http://acx100.sourceforge.net/wiki/ACX

The ZyXEL PCI card is using the Texas Instruments ACX 111 chipset. There is a great open source project located at http://acx100.sourceforge.net providing drivers for Linux users.
Although it might be possible to use the NdisWrapper project, you might have problems finding a working windows driver if you have a 64bit processor (which I do). (As of the date of this blog entry, ZyXEL has no 64bit driver for this card).

The ACX100 project should work with both 32- and 64-bit systems.

The Installation requires

Downloading the Source
Downloading Kernel Source
Downloading Firmware
Compiling Source
Configuration

Downloading the Source

Run the following commands as root

mkdir /usr/src/acx-20051202 cd /usr/src/acx-20051202 wget http://acx100.erley.org/acx-20051202.tar.bz2 tar xjvf acx-20051202.tar.bz2

Downloading Kernel Source

Most probably its already on your machine, if not run

yum install kernel-devel

Downloading Firmware

Download and install the firmware with the following commands

cd /lib/firmware wget http://acx100.erley.org/acx_fw/acx111_netgear_wg311v2/fw1/FwRad16.bin_1.2.1.34 ln -s FwRad16.bin_1.2.1.34 tiacx111c16 ln -s FwRad16.bin_1.2.1.34 FwRad16.bin

Compiling Source

I found that I had to modify the sources a tiny bit to only compile the PCI parts by commenting out the USB parts, in order to get things to work.

Edit the following line in /usr/src/acx-20051202/Makefile

~~acx-obj-y += usb.o~~ #acx-obj-y += usb.o

And in /usr/src/acx-20051202/acx_config.h, edit the following line

~~#define CONFIG_ACX_USB 1~~ //#define CONFIG_ACX_USB 1

Now compile with

make -C /lib/modules/`uname -r`/build M=`pwd`

(Note the difference between back ticks ` and single quote ')

Configuration and Installation

The following instructions assumes the new wireless device is called wlan0, if you are installing multiple devices, replace wlan0 with the device name you'd prefer.

Load the driver with

cd /usr/src/acx-20051202 insmod acx.ko

If this looks ok and dmesg looks ok too, then the driver was successfully loaded into the kernel and the driver is ready to be installed under /lib

cd /usr/src/acx-20051202 make -C /lib/modules/`uname -r`/build M=`pwd` modules_install

All modules installed under /lib/modules/... get loaded at startup. However if the module file (in our case acx.ko) is not executable it seems it is not getting loaded. The install script above copies the acx.ko file to /lib/modules/<kernel-version>/extra/acx.ko but without the proper execution bit. Therefore you must do

chmod 744 /lib/modules/`uname -r`/extra/acx.ko

Next, edit /etc/modprobe.conf and add the following line

alias wlan0 acx

This will tell your system that there exists a wireless card with the acx.ko driver.

Next type

system-config-network

Click New in the upper left corner and basically follow the GUI wizard, here are screen shots of the first few steps. After the final step the system is gonna try connect to your wireless network. Don't get discouraged if it doesn't work right away, just continue reading.

If the wizard fails to connect, try the following

iwlist wlan0 scan

and compare the channel id with the one found in /etc/sysconfig/network-scripts/ifcfg-wlan0

Where I live, this is what iwlist wlan0 scan returns

iwlist wlan0 scan wlan0 Scan completed : Cell 01 - Address: 00:11:14:FA:2B:C3 ESSID:"icegreen" Mode:Master Frequency:2.437 GHz (Channel 6) Quality=41/100 Signal level=18/100 Noise level=0/100 Encryption key:on Bit Rate:54 Mb/s

This is the ifcfg-wlan0 file I ended up with

IPV6INIT=no ONBOOT=yes USERCTL=yes GATEWAY= TYPE=Wireless DEVICE=wlan0 HWADDR=00:51:75:12:d1:10 BOOTPROTO=dhcp NETMASK= DHCP_HOSTNAME= IPADDR= DOMAIN= ESSID=icegreen CHANNEL=6 MODE=Managed

After editing your ifcfg-wlan0 file you don't have to restart your computer, just type

service network restart

which gives better visual feedback over

ifconfig wlan0 up

Note the ONBOOT=yes which will enable your wireless each time you boot up your machine.

Other References

http://www.houseofcraig.net/acx100_howto.php

Did it Work?

It would be nice to hear if my efforts in writing up my experiences with this card are helping others. Please feel free to post a comment or email me if it did.

Installing Tomcat with commons-daemon (jsvc)

Tue, 13 Dec 2005 20:11:57 GMT

Most installation that I've seen of Tomcat is made with tomcat running as root. This could potentially be a disasters security hole. Most Linux systems only allow the root to listen to port 80...which is why many users of tomcat under Linux run tomcat as root. With jscv, the process will start off as root but later on will change owner to a user of your choice.