add device to raid

To create a RAID10 do the following
mdadm --create /dev/md0 --level=10 --raid-devices=4 /dev/sda /dev/sdb /dev/sdc /dev/sdd

to insert a new hard disc by replacing a broken one do
mdadm --manage /dev/md?? --add /dev/newpartition

to monitor your RAID and to send an email if a disc fails:
mdadm --monitor --scan --mail=office@wimmer-christian.de

Midnight Commander shows strange characters

If mc shows strange characters (lines are not drawn, ...) then the shell variable
LANG is not set correctly.
You can change the LANG variable permanently to be en_US.ISO-8859-1 like

echo "export LANG=en_US.ISO-8859-1" | sudo tee -a /etc/bash.bashrc

or just for the mc :

echo "alias mc='export LANG=en_US; mc'" | sudo tee -a /etc/bash.bashrc

Both worked for me.

error message when compiling v4l-dvb-experimental

if you get an error message like usage_count... then just comment this lines in that files.

tvtime, kwintv, xawtv no sound

Execute this line after you started the application. Maybe you need to do this as root

sox -w -r 32000 -t ossdsp /dev/dsp3 -t ossdsp /dev/dsp

please adjust /dev/dscp3 and /dev/dsp to your needs.

xawtv liefert X Error of failed request: XF86DGANoDirectVideoMode

xawtv -c /dev/video -remote -global:filter "linear bend"

printing DHL postage stamp

If you want to make a test print with acroread (i.e. to print a DHL postage stamp)
and you get the error message "lp: The printer or class was not found"
then set up the default printer to have the name "undefined".
You can do this via hp-setup -a. Only if it looks like this:
linux>lpq
undefined is ready
no entries
linux>

then you can print.

encryption

-> /etc/init.d/boot.crypto start to start the encryption daemon
-> give the passwords
-> dmsetup ls
shows the encrypted devices
-> mount "device" "directory"
mounts the "device" to the "directory"
-> cryptsetup remove "device"
removes the link and after this it can not be mounted again.

by hand procedure

losetup /dev/loop0 soft_08062008 (soft_08062008 is a file)
cryptsetup luksOpen /dev/loop0 softcont (softcont is any name)
mount /dev/mapper/softcont softcontainer (softcontainer is the directory where the data will be mounted)

Attention:
cryptsetup luksFormat /dev/loop0 will format the file
cryptsetup luksClose softcont will detach the mapping