Changed: 2013-05-24 15:40:53
Finally got myself a nice APC UPS. A Back-UPS CS 500 to be precise. A UPS is a box containing a battery so that a desktop-PC in case of powerfailure can savely shutdown.
I bought it second-hand for €20,- , but when I received it it turned out the battery had to be replaced, which costs another €35,-. Then I needed the proprietary data-cable, which would have costed €35,- which is insane for a simple USB-cable.
This data-cable is needed so the computer knows when power is down and the battery is draining. When the power gets down it send an email, so when I am away from home I know there's something wrong. Another nice feature is that this way you can measure the powerconsumption and calculate the money it costs on energy. You can use the UPS without this cable, but it won't shut down automatically. If it's only for a PC you work on, this might be enough, but for a 24/7-server this is not very useful. If you have the data-cable you can use apcupsd for Linux to control it and read the values.
I decided to create a cable my own according to this pinout scheme. It turns out that it's just a simple USB-cable. I bought myself a second-hand, 75ct mouse for the usb-cable and then I needed the very uncommon connector to plug into the UPS. This turned out to be a 10p10c-connector, which looks very similar to a RJ-45 connector used for network-cables, but this connector has 10 connections instead of 8. I could get this connectors from electronic-webshop conrad.nl for 90ct a piece.
I did have a good RJ-45-tool for networkcables, and when used with these 10p10c-connectors it closes 8 out of 10 of the connections nicely. The two outer connections had to be closed using a plier and a small screwdriver.
This particular version has a capacity of 500VA and 300W: My PC/server consumes 30% of that which calculates to about 16 minutes of battery power. I plan to also connect one monitor and the modem to it, which makes this time of course shorter.
Changed: 2013-03-30 17:35:40
I have an Asus Laptop A55VD and it took me some time to get the backlight working. That was quite an issue because on battery power the battery was quickly drained if the backlight was on full brightness.
Having a look in /sys/class/backlight I had acpi_video0 and acpi_video1.
After changing the kernel command line to include:
I had two devices in /sys/class/backlight:
asus-nb-wmi and intel_backlight
The intel_backlight interface worked, but the asus-nb-wmi-interface not, but KDE4 insisted on using the asus-nb-wmi-interface.
So finally decided to blacklist the asus-nb-wmi kernel module; According to the explanation this module is supposed to make certain hotkeys working, but I haven't found any hotkeys which stopped working after unloading this module.
The Fn+Brightness++ and Fn+Brightness-- buttons didn't work with or without the kernel-module.
So without this module loaded I have only left intel_backlight in /sys/class/backlight and KDE4 is using it.
Changed: 2013-02-11 20:29:32
My telecom-provider comes with a Comtrend modem but unfortuantely the provider has decided that it's easier for them if they switch off all configurations. Since I like to set several custom preferences for my home-network this is a big problem. It's also impossible to replace it with an own modem/router. The only way to solve (most of) the problems was to buy a router and put it in between the modem and the LAN. But why buying a router if I have a server running 24/7?
First I bought a PCI-network for my server. it's a 10/100Mbits card because I couldn't care for Gigabit-LAN. The I had to rebuild the kernel because I didn't have the driver for it.
The on-board ethernet-card is eth0 and the extra card is eth1.
On the server runs shorewall as a firewall, so I used this for the routing. First I had to add the new networkinterface to /etc/shorewall/interfaces and /etc/shorewall/policy
Now my firewall is much saver because I can open up all the fun stuff to the LAN while keeping the evil internet locked out.
in /etc/shorewall/masq i have the following rule:
For DHCP and DNS I used dnsmasq wich is a lightweight alternative to bind and DHCPd.
For uPnP I used miniupnpd. Unfortunately this program is made to cooperate with iptables, not with shorewall so I had to modify the init script and the shorewall files to make it work. In some tutorials I found the name of linux-igd, but this is not in the Gentoo-repo anymore.
Changed: 2013-02-11 20:26:23
Now I have the /etc directory in subversion. It's a bit tricky because I didn't find a way yet to do without overwriting all the files.
I read this page but I had to change several commands, probably because this page is from 2006.
Please, don't copy and paste the commands on this page because I didn't check them when writing them here.
I have a 'working copy' in /server-vcs/myserver-name. My laptop has another directory in SVN in the /server-vcs directory.
I have svnserve running so I'm using svn://blabla URLs
Basically it starts with copying the /etc directory to somewhere save
then putting the following line in /etc/fstab
/etc /server-vcs/myserver-name/etc none bind
and mount it
then make a base-dir in the repo:
svn mkdir svn://svn-server/repos/server-vcs
then import all the files into SVN
svn import /server-vcs svn://svn-server/repos
then pull them all out
svn co svn://server-vcs/repos/server-vcs
and then the overwrite part to make it consistent
svn revert -R /server-vcs
now you can cd into /server-vcs/myserver-name
and then do
svn status to see if there's anything modified
to update the SVN repo whenever anything has changed.
Changed: 2012-09-21 12:30:32
It seems to be a common problems with Nokia smartphones with Symbian S60: Gradually the system partitions fills up with in the end even the phone not working anymore.
The system partition (C:) is 65MB and in the end only 7MB was left.
It advises to remove all messages, but this didn't really help. Then, according to some tip I removed the email accounts in Nokia email, which resulted in a mere 10MB free space.
Then I removed the email app entirely and also Nokia Maps. This made 45MB of space free.
Changed: 2012-09-21 12:31:04
Gradually the root partition of my PC/server filled up and became too small.
So, how to resize a root partition?
Luckily I had a separate /home partition which was very big and it was placed after the root partition.
Resizing the home partition could even be done on a live system if you're re not logged in as user but as root.
But I couldn't find a way to make KDM let me login as root in a graphical environment so I decided to use the parted USB-live-CD.
This Boot-USB-stick provided a complete graphical gparted partition tool so I could easily shrink and move the home partition and after that make the root partition bigger. It took about 6 hours to move 80GB of the home partition.
The root partition is now 200GB and the /home is 400GB
Changed: 2012-09-21 00:00:51
Because of some failed experiment I damaged libc on my laptop with Gentoo Linux.
Kind of a problem because virtually all software is linked with that libc and when this is damaged or has the wrong version no program is working anymore, not even the login shell. So, how to repair this?
Finally I found a way using the Live DVD of Gentoo. Trying to compile and install a new ibc from this DVD didnᷰ t work because the laptop was overheating during the process. The kernel on the DVD didnᷰ t contain the powernow module needed for CPU frequency scaling.
Finally I downloaded a stage3 from the Gentoo site and overwrote all the system files on the laptop with this stage3
Then I had a working and booting laptop, although many programs complained about a wrong (old) libc version.
At the moment the laptop is rebuilding the system files (@system). If this succeeds, I do a complete rebuild (@world).
Rebuild @system takes about 1 day, rebuilding @world takes 3 days
By the way, the failed experiment was using distcc to distribute the compiling between computers.
Changed: 2012-09-21 12:33:19
Since some time I have a new tablet, an Asus TF300T. It's a kind of hybride tablet/netbook with detachable keyboard. It's a 10" tablet with quad-core processor and Android 4.1.1 (Jelly Bean)
Of course this one is much faster and better than the slightly unreliable budget-tablet I bought earlier.
I have to get used to the not so free restrictions of an Android system. It is possible to 'root' it, but I would lose warranty, and more important firmware updates with it.
It's also not so nice that Google stopped supporting Flash on the newest Android (Jelly Bean).
After a while I will post a nice list of Android favorite apps.
Changed: 2012-08-07 18:51:03
At the moment I'm playing an addiction Android game on my tablet, Fashion Story. It's a simulation of a fashion boutique.
Changed: 2012-06-26 19:19:20
It's a Cherry Mobile M-728 ProLine, apparently just a Hyundai A7HD. It's sold at Dutch 'Kruidvat' drugstores. It has Android 4.0 and 1.2GHz Cortex ARM processor.
I think am not a very average user because my first app to install was a (SSH-)terminal and within a week I already opened it to solve a common problem with the WiFi-antenna.
Now I can play around with Android, tweaking it and it's also useful to test my websites.
Changed: 2012-05-25 18:20:23
In 2008 I bought my laptop, to be precise, a HP DV7 1010ed, with 1800Mhz. dual-core AMD Athlon. Since the beginning I had this problem with overheating, although an average Windows user would blame it on Windows Vista. Because of this overheating the processor throttles down which makes the laptop very slow. An average Windows user might not notice, but as a Linux user I can see it's almost continuously in low frequency mode.
Even worse, Linux doesn't install this frequency scaler risking the laptop to be overheating and forcely shutdown by hardware. Unfortunately the €120,- battery get damaged by such a hardware shutdown, which is in my opinion a design-fault as well.
another cause for the overheating is that I have smoked a lot while using the laptop, so the internal are covered with a layer of tar and nicotine. To clean the fan and the heatsink I have to entirely disassemble the laptop, which in my opinion is another design-fault.
By emerging and configuring cpufreqd I can avoid most, but not all hardware shutdowns. The in-kernel frequency governors throttle down based on load, but with cpufreqd I can make it throttle down on high temperature.
Without additionally cooling in an laptoppad it's impossible to use processor-intensive application like compiling or even programming in Netbeans.
Lately something went wrong with installing the kernel modules resulting in a situation that I could only repair it by recompiling the kernel. Without the modules needed for frequency scaling this was impossible, so in the end I got the kernel recompiled in a chroot environment from the Gentoo install disk.
But what's the use of a fast laptop if most of the time it runs at half speed because of the overheating?
Changed: 2012-05-24 00:44:39
My HP laptop has a Radeon 3400-series graphics card. For (Gentoo) Linux I'm using the kernel-included opensource Radeon driver with KMS-modesetting. Recently I read that this card is not even supported anymore by the next version of ATI/AMD's own proprietary driver (the laptop is from 2008).
This driver worked very well as a module, but I wanted it to include in the kernel for early loading of my nice graphic bootscreen. For a long time I couldn't get it to work, but here are my settings which worked for me:
First emerge radeon-ucode.
Then (for Linux kernel 3.4.0):
# CONFIG_PREVENT_FIRMWARE_BUILD is not set
# CONFIG_FIRMWARE_IN_KERNEL is not set
CONFIG_EXTRA_FIRMWARE="radeon/RV620_pfp.bin radeon/RV620_me.bin radeon/R600_rlc.bin"